Update apt.mdx
Update apt.mdx

- Removed usage of `apt-key` which is deprecated and replaced by `gpg` command
- Removed usage of `curl` command which is not present by default on Debian systems
hashicorp/terraform,tommynsong/terraform,tommynsong/terraform,tommynsong/terraform,rnaveiras/terraform,hashicorp/terraform,rnaveiras/terraform,hashicorp/terraform,rnaveiras/terraform