chore(renovate): update GitHub Actions major versions in docs

[mkniewallner]

Summary

Originally wanted to update the reference to astral-sh/setup-uv in https://docs.astral.sh/uv/guides/integration/github/, but thought it could be nice to automate those updates through Renovate. The custom manager will look for any major version GitHub Action reference in any Markdown file in docs directory, and raise a PR to update it.

Possible improvements:

• We could separate those updates from updating the actions updates for uv's own GitHub Actions workflow, which would end up raising 2 different PRs instead of grouping them (example of the current behaviour without this improvement in Update actions/checkout action to v4 mkniewallner/mkv-playground#4 where we update the doc reference at the same time as a real dependency usage in a workflow).
• Should the PRs be raised immediately, to handle the update as soon as possible, instead of waiting for the regular weekly Monday schedule? This would ensure that astral-sh/setup-uv references are handled as early as possible. done in 6af7f45

Test Plan

I've tested that with https:/mkniewallner/mkv-playground/blob/00ddfb69003843ad57d05f9ef036e655aaf765d7/renovate.json5 and https:/mkniewallner/mkv-playground/blob/00ddfb69003843ad57d05f9ef036e655aaf765d7/docs/integeration/foo.md, where Renovate raised 2 PRs:

• Update dependency astral-sh/setup-uv to v3 - autoclosed mkniewallner/mkv-playground#13
• Update actions/checkout action to v4 mkniewallner/mkv-playground#4

[zanieb]

Thank you! This is great.

I don't mind a weekly cadence.

Separate pull requests seems kind of nice? But maybe not necessary. Is it hard to do? I'm willing to wait and see if it's problematic.

[mkniewallner]

Separate pull requests seems kind of nice? But maybe not necessary. Is it hard to do? I'm willing to wait and see if it's problematic.

I don't think it's hard to do, will play with that in my test repository then update this PR (or report back if this is in the end).

[mkniewallner]

Separate pull requests seems kind of nice? But maybe not necessary. Is it hard to do? I'm willing to wait and see if it's problematic.

I don't think it's hard to do, will play with that in my test repository then update this PR (or report back if this is in the end).

Played with that in mkniewallner/mkv-playground@4c3ea0d (inspired by an example from Renovate itself), and it works well:

• real dependency usage: https:/mkniewallner/mkv-playground/pull/4/files
• dependency reference in the documentation: https:/mkniewallner/mkv-playground/pull/16/files