Migrate from Travis CI to GitHub Actions. (#381)

* Migrate from Travis CI to GitHub Actions.

Travis CI is moving to billed plans per https://blog.travis-ci.com/2020-11-02-travis-ci-new-billing. Volley's requirements are simple and should work fine with GitHub Actions, which would hopefully be supported as long as GitHub itself is.

Co-authored-by: Joe Bowbeer <joe.bowbeer@gmail.com>

.github/workflows/gradle-build.yaml

@@ -0,0 +1,28 @@
+name: Gradle
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK 1.8
+        uses: actions/setup-java@v1
+        with:
+          java-version: 1.8
+      - name: Cache Gradle packages
+        uses: actions/cache@v2
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
+          restore-keys: ${{ runner.os }}-gradle
+      - name: Build with Gradle
+        run: ./gradlew --continue verifyGoogleJavaFormat build connectedCheck
+      - name: Publish snapshot
+        if: github.event_name == 'push'
+        env:
+          CI_DEPLOY_USERNAME: ${{ secrets.CI_DEPLOY_USERNAME }}
+          CI_DEPLOY_PASSWORD: ${{ secrets.CI_DEPLOY_PASSWORD }}
+        run: ./publish-snapshot-on-commit.sh

publish-snapshot-on-commit.sh

@@ -1,13 +1,15 @@
 set -eu
 
-if [ "$TRAVIS_REPO_SLUG" == "google/volley" ] && \
-   [ "$TRAVIS_PULL_REQUEST" == "false" ] && \
-   [ "$TRAVIS_BRANCH" == "master" ]; then
+GITHUB_BRANCH=${GITHUB_REF#refs/heads/}
+
+if [ "$GITHUB_REPOSITORY" == "google/volley" ] && \
+   [ "$GITHUB_EVENT_NAME" == "push" ] && \
+   [ "$GITHUB_BRANCH" == "master" ]; then
   echo -e "Publishing snapshot build to OJO...\n"
 
   ./gradlew artifactoryPublish
 
   echo -e "Published snapshot build to OJO"
 else
   echo -e "Not publishing snapshot"
-fi
+fi