Add step to make mvnw executable in CI workflow

.github/workflows/ci.yml

@@ -29,11 +29,12 @@ jobs:
           key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
           restore-keys: |
             ${{ runner.os }}-maven-
+      - name: Make mvnw executable
+        run: chmod +x ./mvnw
       - name: Build with Maven
         run: ./mvnw clean package
       - name: Run tests
         run: ./mvnw test
-
   docker:
     needs: build
     runs-on: ubuntu-latest