chore: move code style verification to GitHub Actions job

.github/workflows/main.yml

@@ -12,6 +12,20 @@ on:
 # GitHub Actions does not support Docker, PostgreSQL server on Windows, macOS :(
 
 jobs:
+  ubuntu-code-style:
+    name: 'Ubuntu, code style (JDK 8)'
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 50
+    - name: 'Set up JDK 8'
+      uses: actions/setup-java@v1
+      with:
+        java-version: 8
+    - name: 'Verify code style'
+      run: ./gradlew autostyleCheck checkstyleAll
+
   ubuntu-latest:
     name: 'Ubuntu, PG latest (JDK 8)'
     runs-on: ubuntu-latest
@@ -37,7 +51,7 @@ jobs:
 #          --health-timeout 5s
 #          --health-retries 5
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v2
       with:
         fetch-depth: 50
     - name: Start PostgreSQL

.travis.yml

@@ -89,10 +89,7 @@ matrix:
   fast_finish: true
   include:
     - stage: test
-      jdk: oraclejdk8
-      env: RUN_CHECKSTYLE=true
-      script: ./gradlew autostyleCheck checkstyleAll
-    - env:
+      env:
         - FEDORA_CI=Y
       services:
         - docker