Updates all actions to latest versions

[stumpylog]

Description:

Related issue (if applicable): None

This PR updates all the actions to the latest versions, dealing with any breaking changes (mostly that's just some syntax for docker/metadata-action). This will remove all those pesky warnings about deprecated Node versions and usages of old style output setting.

To help keep them updated, a dependabot configuration file for monthly checks for action updates is added as well.

An example run is here: https://github.com/stumpylog/apprise-api/actions/runs/6869096389
The failure is merely due to the attempt to push, the actual build is fine.

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• No lint errors (use flake8)
• Tests added

[caronc]

Thank you for this!

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.16%. Comparing base (46d9533) to head (782c2f5).
Report is 45 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #149   +/-   ##
=======================================
  Coverage   95.16%   95.16%           
=======================================
  Files           7        7           
  Lines         703      703           
=======================================
  Hits          669      669           
  Misses         34       34           

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