CI: Skip SimpleCov collating on Rubies below 2.7

[kaylareopelle]

Description

Let's resolve the warning annotations on our CI actions

Skip SimpleCov collating on Rubies below 2.7

Currently, we're getting annotations like: No files were found with the provided path: lib/coverage_*/.resultset.json. No artifacts will be uploaded. for test runs with Rubies below 2.7 on PRs.

Node JS and deprecation warnings

There are other annotations related to dropping support for Node 12 and having certain actions deprecated.

Acceptance Criteria

CI has no warning annotations
Artifacts are not attempted to be created on Rubies below 2.7

Additional context

Nice to have, it's a bit messy/misleading to have this show up on passing tests

Estimates

S

[workato-integration]

https://issues.newrelic.com/browse/NEWRELIC-3390