ci: setup njsscan

See: https://github.com/ajinabraham/njsscan-action

Signed-off-by: David Mehren <git@herrmehren.de>

.github/workflows/njsscan-analysis.yml

@@ -0,0 +1,31 @@
+# SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+#
+# SPDX-License-Identifier: AGPL-3.0-only
+
+name: "Njsscan Analysis"
+
+on:
+  push:
+    branches: [ develop ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ develop ]
+  schedule:
+    - cron: '0 7 * * 6'
+
+jobs:
+  njsscan:
+    runs-on: ubuntu-latest
+    name: Njsscan code scanning
+    steps:
+    - name: Checkout the code
+      uses: actions/checkout@v2
+    - name: Scan with njsscan
+      id: njsscan
+      uses: ajinabraham/njsscan-action@master
+      with:
+        args: '--sarif --output results.sarif src || true'
+    - name: Upload njsscan report
+      uses: github/codeql-action/upload-sarif@v1
+      with:
+        sarif_file: results.sarif