Bump actions/cache from 3 to 4 (#648)

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

Author: dependabot[bot]

.github/workflows/continuous_integration.yml

@@ -44,7 +44,7 @@ jobs:
           echo "::set-output name=dir::$(composer config cache-files-dir)"
 
       - name: composer-cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ${{ steps.composercache.outputs.dir }}
           key: composer-${{ hashFiles('**/composer.json') }}-${{ matrix.install-args }}
@@ -61,7 +61,7 @@ jobs:
         run: "vendor/bin/phpunit"
 
       - name: phpstan-cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           key: phpstan-${{ matrix.php-version }}-${{ matrix.install-args }}-${{ github.ref }}-${{ github.sha }}
           path: .phpstan-cache