Bump actions/cache from 3 to 4 (#144)

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>

.github/workflows/build.yml

@@ -10,7 +10,7 @@ jobs:
         id: cache_key
         run: echo "gradle_key=gradle-`cat versions/mainProject`" >> $GITHUB_OUTPUT
       - name: Cache Gradle stuff
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           key: ${{ steps.cache_key.outputs.gradle_key }}-${{ hashFiles('*.gradle.kts', 'gradle.properties', 'gradle/**') }}
           restore-keys: ${{ steps.cache_key.outputs.gradle_key }}-

.github/workflows/test.yml

@@ -31,7 +31,7 @@ jobs:
         id: cache_key
         run: echo "gradle_key=gradle-`cat versions/mainProject`" >> $GITHUB_OUTPUT
       - name: Cache Gradle stuff
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           key: ${{ steps.cache_key.outputs.gradle_key }}-${{ hashFiles('*.gradle.kts', 'gradle.properties', 'gradle/**') }}
           restore-keys: ${{ steps.cache_key.outputs.gradle_key }}-