Setup GitHub actions for build checks

.github/workflows/build.yml

@@ -0,0 +1,23 @@
+name: Build
+on: [ push, pull_request ]
+
+jobs:
+  build:
+    # Only run on PRs if the source branch is on someone else's repo
+    if: ${{ github.event_name != 'pull_request' || github.repository != github.event.pull_request.head.repo.full_name }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        java: [ 8, 11, 17 ]
+      fail-fast: true
+    steps:
+      - uses: actions/checkout@v2.3.5
+      - uses: gradle/wrapper-validation-action@v1
+      - name: JDK ${{ matrix.java }}
+        uses: actions/setup-java@v2.3.1
+        with:
+          java-version: ${{ matrix.java }}
+          cache: 'gradle'
+          distribution: 'temurin'
+      - name: build
+        run: ./gradlew build --stacktrace

.travis.yml

@@ -1,13 +0,0 @@
-sudo: false
-dist: bionic
-
-language: java
-jdk:
-  - openjdk8
-  - openjdk11
-
-install: true
-script: ./gradlew build
-
-notifications:
-  email: false