Apparently, there's no easy way to submit coverage reports from GitHub pull request builds
without exposing this reporter ID. Coverage diff reports should now come in from pull
request builds after this commit. The expectation is that Code Climate will comment on the
pull requests and mark the build as failed or succeeded based on the coverage diff.
This commit also disables sending code coverage reports to Codecov, which has been broken
for a while now: https://github.com/codecov/codecov-action/issues/43
GitHub Actions actions/checkout@v1 checked out code as a detached HEAD,
which caused Code Climate test coverage reports to appear as on the HEAD branch.
Coverage reports should now appear on an upstream branch.
From the actions/checkout@v2 release notes: https://github.com/actions/checkout/blob/v2/README.md
> - Creates a local branch
> - No longer detached HEAD when checking out a branch
> - A local branch is created with the corresponding upstream branch set
