Bump actions/cache from 3 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 3 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v3...v4)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/build-docs.yml

@@ -30,7 +30,7 @@ jobs:
 
       # virtualenv cache should depends on OS, Python version and `poetry.lock` (and optionally workflow files).
       - name: Cache Packages
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: |
             ~/.local

.github/workflows/run-tests.yml

@@ -34,7 +34,7 @@ jobs:
 
       # virtualenv cache should depends on OS, Python version and `poetry.lock` (and optionally workflow files).
       - name: Cache Packages
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         if: ${{ !startsWith(runner.os, 'windows') }}
         with:
           path: |