[CI] Set up gradle for usage in nightly Discord announcer

Author: robotgryphon

.github/workflows/announce-latest-nightly.yml

@@ -25,6 +25,15 @@ jobs:
         with:
           fetch-depth: 0
 
+      - name: Set up JDK
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v3
+
       - name: MC Version
         id: minecraft
         run: ./gradlew mcVersion -q >> "$GITHUB_OUTPUT"