Dodanie checkstyle i integracji ciągłej

Author: gomolkap

.github/workflows/github-actions.yml

@@ -12,4 +12,6 @@ jobs:
           java-version: '17'
           distribution: 'adopt'
       - name: Test
-        run: mvn test
+        run: mvn test
+      - name: runCheckstyle
+        run: mvn checkstyle:checkstyle