Fix docker failure with dangling pid file

[thinkst-pieter]

Proposed changes

When a docker container restarts the twisted pid could be left in a dangling state preventing twisted from starting correctly.

This pull request fixes the stale pid issue by having the pid file in /var/run and the mounting /run as a temporary file system in the docker environment. This fix is in line with the solution we made for our commercial canary offering.

Additionally the github runners for macos are updated and a couple of documentation changes.

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update

Checklist

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• Lint and unit tests pass locally with my changes (if applicable)
• I have run pre-commit (pre-commit in the repo)
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Linked to the relevant github issue or github discussion