CircleCI build enhancements and fixes

[arm4b]

CircleCI is showing some instability and different results in the packaging builds recently. Experiment with the CircleCI environment.

• Update the outdated Docker environment
• Retry docker-pull on failure (helps with noisy build failures unable to download docker images)
• Invalidate the wheelhouse cache, where old cache might bring issues with the el8->rocky switch
• Fix corner case when the same wheelhouse cache/key could be used by all the distros as a fallback

[arm4b]

Update: removed the wheelhouse cache to be consistent with the st2 repo environment: https://github.com/StackStorm/st2/blob/master/.circleci/config.yml

With wheelhouse cache (cache hit):

Wheelhouse cache removed:

Looks like it just provides the 30sec speedup, potentially bringing corner cases with the complex configuration and cache/invalidation.

[amanda11]

@armab Looks great, do you want to merge.