Only run build on PR (no publishing)

.github/workflows/pr.yml

@@ -0,0 +1,27 @@
+name: Java Gradle Build
+
+on:
+  pull_request
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Set up JDK 8
+        uses: actions/setup-java@v2
+        with:
+          java-version: '8'
+          distribution: 'temurin'
+          cache: gradle
+      - name: Build with Gradle
+        run: ./gradlew build
+      - name: Cleanup Gradle Cache
+        # Remove some files from the Gradle cache, so they aren't cached by GitHub Actions.
+        # Restoring these files from a GitHub Actions cache might cause problems for future builds.
+        run: |
+          rm -f ~/.gradle/caches/modules-2/modules-2.lock
+          rm -f ~/.gradle/caches/modules-2/gc.properties

.github/workflows/snapshot.yml

@@ -1,6 +1,9 @@
 name: Java Gradle Snapshot
 
-on: ["push", "pull_request"]
+on:
+  push:
+    branches:
+      - 'main'
 
 jobs:
   build: