Migrate workflow from maven to gradle

.github/workflows/gradle.yml

@@ -0,0 +1,26 @@
+# This workflow will build a Java project with Gradle and cache/restore any dependencies to improve the workflow execution time
+# For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-gradle
+
+name: Java CI with Gradle
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up JDK 8
+      uses: actions/setup-java@v2
+      with:
+        java-version: '8'
+        distribution: 'zulu'
+        cache: gradle
+    - name: Build with Gradle
+      run: ./gradlew build

.github/workflows/maven.yml

@@ -1,27 +0,0 @@
-name: Publish to Github Packages
-
-on: 
-  push:
-    branches:
-      - master
-
-jobs:
-  build:
-
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v1
-    - name: Set up JDK 1.8
-      uses: actions/setup-java@v1
-      with:
-        java-version: 1.8
-    - name: Build with Maven
-      run: mvn -B package --file pom.xml -pl '!brouter-routing-app'
-    - name: Deploy to Github Package Registry
-      env:
-        GITHUB_USERNAME: x-access-token
-        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        GITHUB_REPOSITORY: ${{ github.repository }}
-      run:
-        mvn --settings settings.xml deploy -pl '!brouter-routing-app'