fix: allow manual triggering of promote workflow on workflow_dispatch event

Updated the promote workflow to enable manual triggering in addition to
automatic execution when a pull request is merged. This change enhances
the flexibility of the deployment process.

Author: ATGardner

.github/workflows/promote.yml

@@ -1,14 +1,15 @@
 name: Promote
 
 on:
+  workflow_dispatch:
   pull_request:
     types: [closed]
     branches:
       - main
 
 jobs:
   promote:
-    if: github.event.pull_request.merged == true
+    if: github.event.pull_request.merged == true || github.event_name == 'workflow_dispatch'
     runs-on: ubuntu-latest
     steps:
       - name: Checkout main branch