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/tests.yml

@@ -126,7 +126,7 @@ jobs:
         run: python -m pip install --upgrade tox
 
       - name: Cache tox virtual environment
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: .tox
           key: ${{ matrix.os }}-tox-${{ matrix.python-version }}-${{ hashFiles('pyproject.toml', 'tox.ini') }}
@@ -196,7 +196,7 @@ jobs:
         run: python -m pip install --upgrade tox
 
       - name: Cache tox virtual environment
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: .tox
           key: ubuntu-latest-tox-${{ matrix.python-version }}-${{ hashFiles('pyproject.toml', 'tox.ini') }}
@@ -264,7 +264,7 @@ jobs:
         run: python -m pip install --upgrade tox
 
       - name: Cache tox virtual environment
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: .tox
           key: ubuntu-latest-tox-${{ matrix.python-version }}-${{ hashFiles('pyproject.toml', 'tox.ini') }}