This should allow the same script to be used for two different scenarios:
- ansible-core across multiple versions (not all of which support `--docker` for coverage reports)
- collections (which should always use the `devel` branch for coverage reports)
Due to the recent security incident, use our own copy hosted in S3
to mitigate future risk from running an arbitrary script downloaded from a
remote and untrtusted server.
* Increase fetch depth to reduce the frequency of full test runs for out-of-date PRs.
* Update scripts to match those which will be used in collections.
