add kotlin code checks

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

.github/workflow/check.yml

@@ -0,0 +1,21 @@
+name: Check
+
+on:
+    pull_request:
+        branches: [ master, stable-* ]
+
+jobs:
+    check:
+        runs-on: ubuntu-latest
+        strategy:
+            fail-fast: false
+            matrix:
+                task: [ detekt, ktlint ]
+        steps:
+            -   uses: actions/checkout@v2
+            -   name: Set up JDK 1.8
+                uses: actions/setup-java@v1
+                with:
+                    java-version: 1.8
+            -   name: Check ${{ matrix.task }}
+                run: ./gradlew ${{ matrix.task }}