Simplify Github actions

Consolidate build steps to 1 script this way we don't run multiple builds for pushing a branch and create a PR.

.github/workflows/build.yml

@@ -0,0 +1,48 @@
+name: "Build"
+on:
+  pull_request:
+    paths-ignore:
+      - '.txt'
+      - '*.MD'
+      - '*.md'
+      - 'LICENSE'
+      - 'docs/**'
+  push:
+    tags-ignore:
+      - '*'
+    paths-ignore:
+      - '.txt'
+      - '*.MD'
+      - '*.md'
+      - 'LICENSE'
+      - 'docs/**'
+
+jobs:
+  build:
+    if: |
+      ${{
+      github.event_name == 'pull_request' ||
+      (github.event_name == 'push' &&
+      github.event.pull_request.head.repo.full_name != github.repository)
+      }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        java: [16]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK ${{ matrix.java }}
+        uses: actions/setup-java@v2
+        with:
+          distribution: 'zulu'
+          java-version: ${{ matrix.java }}
+          architecture: x64
+      - name: Cache Maven packages
+        uses: actions/cache@v2.1.5
+        with:
+          path: ~/.m2
+          key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}
+          restore-keys: ${{ runner.os }}-m2
+      - name: Build with Maven
+        run: mvn package