chore(deps): 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] <[email protected]>

Author: dependabot[bot]

.github/workflows/documentation.yml

@@ -24,7 +24,7 @@ jobs:
           python-version: 3.8
 
       - name: Restore pip cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.cache/pip
           key: pip-3.8
@@ -34,15 +34,15 @@ jobs:
         shell: bash
 
       - name: Restore poetry cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: |
             ~/.cache/pypoetry/cache
             ~/.cache/pypoetry/artifacts
           key: poetry-cache-and-artifacts-3.8
 
       - name: Restore virtualenvs
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.cache/pypoetry/virtualenvs
           key: venv-${{ hashFiles('poetry.lock') }}-3.8