chore(build): add github actions for PRs, pushes to master

Author: dbyron-sf

.github/workflows/build.yml

@@ -0,0 +1,28 @@
+name: Branch Build
+
+on:
+  push:
+    branches:
+    - master
+
+env:
+  GRADLE_OPTS: -Dorg.gradle.daemon=false -Xmx2g -Xms2g
+
+jobs:
+  branch-build:
+    # Only run this on repositories in the 'spinnaker' org, not on forks.
+    if: startsWith(github.repository, 'spinnaker/')
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: 11
+      - uses: actions/cache@v1
+        with:
+          path: ~/.gradle
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+      - name: Build
+        run: ./gradlew build --stacktrace

.github/workflows/pr.yml

@@ -0,0 +1,23 @@
+name: PR Build
+
+on: [ pull_request ]
+
+env:
+  GRADLE_OPTS: -Dorg.gradle.daemon=false -Xmx2g -Xms2g
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-java@v1
+      with:
+        java-version: 11
+    - uses: actions/cache@v1
+      with:
+        path: ~/.gradle
+        key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
+        restore-keys: |
+          ${{ runner.os }}-gradle-
+    - name: Build
+      run: ./gradlew build