Prevent untested commits from being mergeable

[aaronmondal]

When a new contributor creates a PR, the testsuite isn't run unless a maintainer enables it.

If such a PR gets an LGTM before enabling the testsuite it creates a situation where the PR is treated as "green" and can be merged without running any tests.

This is flagged as violation of https://github.com/ossf/scorecard/blob/main/docs/checks.md#ci-tests

Example:

• Update README.md for AWS Terraform Deployment #608

[aaronmondal]

Fixed. It's now required to run the pre-commit-checks before working.