add semgrep.yml workflow

.github/workflows/semgrep.yml

@@ -0,0 +1,38 @@
+---
+# Name of this GitHub Actions workflow.
+name: Semgrep
+
+on:
+  pull_request:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+  # Täglicher Scan um 17:20 Uhr UTC.
+  schedule:
+    - cron: "20 17 * * *"
+
+jobs:
+  semgrep:
+    name: semgrep/ci
+    runs-on: ubuntu-latest
+
+    container:
+      image: returntocorp/semgrep
+
+    if: (github.actor != 'dependabot[bot]')
+
+    steps:
+      - name: "🧰 Check out code"
+        uses: actions/checkout@v3
+
+      - name: Run semgrep ci
+        run: semgrep ci --sarif --output=semgrep.sarif
+        env:
+          SEMGREP_APP_TOKEN: ${{ secrets.SEMGREP_APP_TOKEN }}
+
+      - name: Upload SARIF file for GitHub Advanced Security Dashboard
+        uses: github/codeql-action/upload-sarif@v2
+        with:
+          sarif_file: semgrep.sarif
+        if: always()