Update gradle/actions action to v6 (#72)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/build-website.yml

@@ -33,7 +33,7 @@ jobs:
         with:
           python-version: 3.x
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@v4
+        uses: gradle/actions/setup-gradle@v6
       - run: echo "CACHE_ID=$(date --utc '+%V')" >> $GITHUB_ENV
       - uses: actions/cache@v5
         with:

.github/workflows/run-dev-build.yml

@@ -22,6 +22,6 @@ jobs:
           java-version: ${{ matrix.java_version }}
           cache: gradle
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@v4
+        uses: gradle/actions/setup-gradle@v6
       - name: Run Gradle build
         run: ./gradlew build

.github/workflows/run-release-build.yml

@@ -23,7 +23,7 @@ jobs:
           java-version: ${{ matrix.java_version }}
           cache: gradle
       - name: Set up Gradle
-        uses: gradle/actions/setup-gradle@v4
+        uses: gradle/actions/setup-gradle@v6
       - name: Run Gradle build
         run: ./gradlew buildRelease
         env: