Cache Maven dependencies in GHA

Author: acogoluegnes

.github/workflows/test-linux.yml

@@ -25,6 +25,11 @@ jobs:
         uses: actions/setup-java@v1
         with:
           java-version: 1.8
-
+      - name: Cache Maven packages
+        uses: actions/cache@v2
+        with:
+          path: ~/.m2
+          key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}
+          restore-keys: ${{ runner.os }}-m2
       - name: Test
         run: ./mvnw verify -Drabbitmqctl.bin=DOCKER:${{job.services.rabbitmq.id}}