Rubocop dev dependencies/scripts are broken

[Justin-W]

Issue Details

The upgrade to ruby 2.7 (see PR #634) seems to have broken the repository's rubocop scripts.

The root cause seems to be rubocop/rubocop/issues/6621, which was fixed by rubocop/rubocop/pull/6470, which is apparently included in rubocop v0.62.0 (and possibly in rubocop v0.61.0).

Also, note that v0.62 is almost 3 years old now, and the latest release is rubocop v1.23.0. So it may be better to upgrade to a more recent release (than v0.62).

Logs (Please redact all sensitive information in your logs)

% rubocop
unknown keywords: :whitelist_classes, :whitelist_symbols

Repro steps (if necessary, delete otherwise)

1. Followed the env setup instructions in 'docs/development.md'.
2. run rubocop or pushd 'src/bosh_azure_cpi' ; ./bin/rubocop_check ; popd