Add 'github-actions' to enabledManagers in renovate.json

[jimboid]

Since moving to rennovate, the actions have not been kept up to date like dependabot did. The enabledManagers works as an allow list. So on enabling pep, this activates python deps but then disables all other update managers.. This should fix that.

[coveralls]

Coverage Report for CI Build 29759099006

Coverage remained the same at 56.949%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	1252
Covered Lines:	713
Line Coverage:	56.95%
Coverage Strength:	1.71 hits per line

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💛 - Coveralls

[harryswift01]

This is a great spot, I was wondering why it has been quiet on the actions side, thanks for adding this in, I'll make sure this is added to all of the other repos if this works nicely.