auto-run prune job on completion of build and publish job

.github/workflows/poll-llama-cpp.yaml

@@ -2,7 +2,7 @@ name: Poll llama.cpp & Trigger Build
 
 on:
   schedule:
-    - cron: '0 * * * *'
+    - cron: '0 */4 * * *'
   workflow_dispatch:
 
 permissions:

.github/workflows/prune-old-toolboxes.yml

@@ -9,6 +9,10 @@ on:
       keep:
         description: Number of latest tags to keep
         default: "3"
+  workflow_run:
+    workflows: ["Build & Publish AMD Strix Halo Toolboxes"]
+    types: [completed]   # runs after success/failure/cancel
+    branches: [main]     
 
 jobs:
   prune: