Configure concurrency to cancel builds in-progress

Author: adamgraham

.github/workflows/generate_docs.yml

@@ -6,6 +6,10 @@ on:
       - main
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 env:
   BASE_PATH: com.zigurous.tweening
   PACKAGE_TITLE: "Tweening System"