Adopt coverity workflow from A4091.device

.github/workflows/coverity.yml

@@ -0,0 +1,21 @@
+name: Coverity Scan
+
+# We only want to test official release code, not every pull request.
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+jobs:
+  coverity:
+    runs-on: ubuntu-latest
+    container: stefanreinauer/amiga-gcc
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        submodules: true
+    - uses: reinauer/coverity-scan-action@v1
+      with:
+        configure: --compiler m68k-amigaos-gcc --comptype gcc --template
+        email: ${{ secrets.COVERITY_SCAN_EMAIL }}
+        token: ${{ secrets.COVERITY_SCAN_TOKEN }}