Use Github Actions workflow for PRs and remove Travis

Closes gh-8716

.github/workflows/pr-build-workflow.yml

@@ -0,0 +1,22 @@
+name: PR Build
+
+on: pull_request
+
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK
+        uses: actions/setup-java@v1
+        with:
+          java-version: '8'
+      - name: Cache Gradle packages
+        uses: actions/cache@v2
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
+      - name: Build with Gradle
+        run: ./gradlew clean build --continue