Use action to run run gradlew build on prs

Author: PetteriM1

.github/workflows/pull-request.yml

@@ -0,0 +1,24 @@
+name: Build PR
+
+on:
+  pull_request:
+    branches:
+      - '3.0'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '8'
+      - name: Validate Gradle Wrapper
+        uses: gradle/actions/wrapper-validation@v4
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
+        with:
+          gradle-version: wrapper
+      - name: Build
+        run: ./gradlew build