Run `apt update`
Run `apt update`

Without this we see:
```
$ sudo apt install gcc-aarch64-linux-gnu

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

Reading package lists...
Building dependency tree...
Reading state information...
The following additional packages will be installed:
  binutils-aarch64-linux-gnu cpp-9-aarch64-linux-gnu cpp-aarch64-linux-gnu
  gcc-10-cross-base gcc-9-aarch64-linux-gnu gcc-9-aarch64-linux-gnu-base
  gcc-9-cross-base libasan5-arm64-cross libatomic1-arm64-cross
  libc6-arm64-cross libc6-dev-arm64-cross libgcc-9-dev-arm64-cross
  libgcc-s1-arm64-cross libgomp1-arm64-cross libitm1-arm64-cross
  liblsan0-arm64-cross libstdc++6-arm64-cross libtsan0-arm64-cross
  libubsan1-arm64-cross linux-libc-dev-arm64-cross
Suggested packages:
  binutils-doc gcc-9-locales cpp-doc gcc-9-doc manpages-dev
  gdb-aarch64-linux-gnu gcc-doc
The following NEW packages will be installed:
  binutils-aarch64-linux-gnu cpp-9-aarch64-linux-gnu cpp-aarch64-linux-gnu
  gcc-10-cross-base gcc-9-aarch64-linux-gnu gcc-9-aarch64-linux-gnu-base
  gcc-9-cross-base gcc-aarch64-linux-gnu libasan5-arm64-cross
  libatomic1-arm64-cross libc6-arm64-cross libc6-dev-arm64-cross
  libgcc-9-dev-arm64-cross libgcc-s1-arm64-cross libgomp1-arm64-cross
  libitm1-arm64-cross liblsan0-arm64-cross libstdc++6-arm64-cross
  libtsan0-arm64-cross libubsan1-arm64-cross linux-libc-dev-arm64-cross
0 upgraded, 21 newly installed, 0 to remove and 17 not upgraded.
Need to get 26.4 MB of archives.
After this operation, 99.8 MB of additional disk space will be used.
Ign:1 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 gcc-9-aarch64-linux-gnu-base amd64 9.3.0-17ubuntu1~20.04cross2
Ign:2 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 cpp-9-aarch64-linux-gnu amd64 9.3.0-17ubuntu1~20.04cross2
Get:3 http://azure.archive.ubuntu.com/ubuntu focal/main amd64 cpp-aarch64-linux-gnu amd64 4:9.3.0-1ubuntu2 [3432 B]
Get:4 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 gcc-10-cross-base all 10.3.0-1ubuntu1~20.04cross1 [15.2 kB]
Get:5 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 binutils-aarch64-linux-gnu amd64 2.34-6ubuntu1.3 [2774 kB]
Err:1 http://security.ubuntu.com/ubuntu focal-updates/main amd64 gcc-9-aarch64-linux-gnu-base amd64 9.3.0-17ubuntu1~20.04cross2
  404  Not Found [IP: 52.252.75.106 80]
Ign:6 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 gcc-9-cross-base all 9.3.0-17ubuntu1~20.04cross2
Get:7 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libc6-arm64-cross all 2.31-0ubuntu9.2cross1 [1041 kB]
Err:2 http://security.ubuntu.com/ubuntu focal-updates/main amd64 cpp-9-aarch64-linux-gnu amd64 9.3.0-17ubuntu1~20.04cross2
  404  Not Found [IP: 52.252.75.106 80]
Get:8 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libgcc-s1-arm64-cross all 10.3.0-1ubuntu1~20.04cross1 [34.6 kB]
Get:9 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libgomp1-arm64-cross all 10.3.0-1ubuntu1~20.04cross1 [91.3 kB]
Get:10 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libitm1-arm64-cross all 10.3.0-1ubuntu1~20.04cross1 [23.7 kB]
Get:11 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libatomic1-arm64-cross all 10.3.0-1ubuntu1~20.04cross1 [9524 B]
Err:6 http://security.ubuntu.com/ubuntu focal-updates/main amd64 gcc-9-cross-base all 9.3.0-17ubuntu1~20.04cross2
  404  Not Found [IP: 52.252.75.106 80]
Ign:12 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libasan5-arm64-cross all 9.3.0-17ubuntu1~20.04cross2
Get:13 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 liblsan0-arm64-cross all 10.3.0-1ubuntu1~20.04cross1 [800 kB]
Get:14 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libtsan0-arm64-cross all 10.3.0-1ubuntu1~20.04cross1 [1964 kB]
Err:12 http://security.ubuntu.com/ubuntu focal-updates/main amd64 libasan5-arm64-cross all 9.3.0-17ubuntu1~20.04cross2
  404  Not Found [IP: 52.252.75.106 80]
Get:15 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libstdc++6-arm64-cross all 10.3.0-1ubuntu1~20.04cross1 [422 kB]
Get:16 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libubsan1-arm64-cross all 10.3.0-1ubuntu1~20.04cross1 [764 kB]
Ign:17 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libgcc-9-dev-arm64-cross all 9.3.0-17ubuntu1~20.04cross2
Ign:18 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 gcc-9-aarch64-linux-gnu amd64 9.3.0-17ubuntu1~20.04cross2
Get:19 http://azure.archive.ubuntu.com/ubuntu focal/main amd64 gcc-aarch64-linux-gnu amd64 4:9.3.0-1ubuntu2 [1420 B]
Err:17 http://security.ubuntu.com/ubuntu focal-updates/main amd64 libgcc-9-dev-arm64-cross all 9.3.0-17ubuntu1~20.04cross2
  404  Not Found [IP: 52.252.75.106 80]
Get:20 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 linux-libc-dev-arm64-cross all 5.4.0-59.65cross1 [1052 kB]
Get:21 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 libc6-dev-arm64-cross all 2.31-0ubuntu9.2cross1 [2041 kB]
Err:18 http://security.ubuntu.com/ubuntu focal-updates/main amd64 gcc-9-aarch64-linux-gnu amd64 9.3.0-17ubuntu1~20.04cross2
  404  Not Found [IP: 52.252.75.106 80]
Fetched 11.0 MB in 1s (15.7 MB/s)
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/g/gcc-9-cross/gcc-9-aarch64-linux-gnu-base_9.3.0-17ubuntu1~20.04cross2_amd64.deb  404  Not Found [IP: 52.252.75.106 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/g/gcc-9-cross/cpp-9-aarch64-linux-gnu_9.3.0-17ubuntu1~20.04cross2_amd64.deb  404  Not Found [IP: 52.252.75.106 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/g/gcc-9-cross/gcc-9-cross-base_9.3.0-17ubuntu1~20.04cross2_all.deb  404  Not Found [IP: 52.252.75.106 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/g/gcc-9-cross/libasan5-arm64-cross_9.3.0-17ubuntu1~20.04cross2_all.deb  404  Not Found [IP: 52.252.75.106 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/g/gcc-9-cross/libgcc-9-dev-arm64-cross_9.3.0-17ubuntu1~20.04cross2_all.deb  404  Not Found [IP: 52.252.75.106 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/g/gcc-9-cross/gcc-9-aarch64-linux-gnu_9.3.0-17ubuntu1~20.04cross2_amd64.deb  404  Not Found [IP: 52.252.75.106 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
```

petermattis/goid,petermattis/goid