Add stub for Checks workflow

Author: Youw

.github/workflows/checks.yml

@@ -0,0 +1,16 @@
+name: Checks
+run-name: Code checks for ${{ github.ref_name }}
+
+on: 
+  workflow_dispatch:
+
+jobs:
+  coverity-macos:
+    runs-on: macos-latest
+
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        path: src
+    - name: Install dependencies
+      run: brew install ninja