Some dependencies upgrades (#1652)

* Some dependencies upgrades

* This PR is also for trying GH Actions in action

* * Fix `pr-build-workflow.yml` trailing whitespaces and indents
* Fix Checkstyle upgrade compatibility
* Fix Checkstyle violations in the code

* * Remove `.travis.yml`
* Fix `updateCopyrights` task to rely on the `GITHUB_ACTION` env var now
* Add `distributionSha256Sum` into `gradle-wrapper.properties` as it is recommended by GH Actions

.github/workflows/pr-build-workflow.yml

@@ -12,15 +12,15 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
-    - name: Set up JDK 11
-      uses: actions/setup-java@v1
-      with:
-        java-version: 11
-        
-    - name: Run Gradle
-      uses: burrunan/gradle-cache-action@v1
-      env:
-        GRADLE_ENTERPRISE_URL: https://ge.spring.io/
-      with:
-        arguments: check
+      - uses: actions/checkout@v2
+      - name: Set up JDK 11
+        uses: actions/setup-java@v1
+        with:
+          java-version: 11
+
+      - name: Run Gradle
+        uses: burrunan/gradle-cache-action@v1
+        env:
+          GRADLE_ENTERPRISE_URL: https://ge.spring.io/
+        with:
+          arguments: check