chore(deps): bump actions/cache from 5.0.5 to 6.0.0 (#2079)

Bumps [actions/cache](https://github.com/actions/cache) from 5.0.5 to 6.0.0.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@27d5ce7...2c8a9bd)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -35,7 +35,7 @@ jobs:
           # Required by lib/github/commands/rest2html (RST rendering)
           python-version: "3.x"
 
-      - uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
+      - uses: actions/cache@2c8a9bd7457de244a408f35966fab2fb45fda9c8 # v6.0.0
         with:
           path: ~/.cache/pip
           key: ${{ runner.os }}-pip