ci: Make Gradle cache actually work

Author: VidTu

.github/workflows/build.yml

@@ -13,7 +13,8 @@ jobs:
         with:
           java-version: 8
           distribution: 'temurin'
-          cache: gradle
+      - name: Setup Gradle
+        uses: gradle/gradle-build-action@v2
       - name: 'Make wrapper executable'
         run: chmod +x ./gradlew
       - name: 'Build'