[ci] add RUSTSEC-2020-0146 to nightly ignore list
[ci] add RUSTSEC-2020-0146 to nightly ignore list

The vulnerable version of generic-array is a transitive dep.

Closes: #8011

libra/libra,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,libra/libra,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core