move to github actions instead of app.abaplint.org (#3463)

* Update and rename ci.yml to build.yml

* Create lint.yml

.github/workflows/build.yml

@@ -1,4 +1,4 @@
-name: CI
+name: build
 
 on: [push, pull_request]
 

.github/workflows/lint.yml

@@ -0,0 +1,15 @@
+name: lint
+
+on: [push, pull_request]
+
+jobs:
+  lint:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: abaplint
+      uses: abaplint/actions-abaplint@master
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}