ci: add workflow_dispatch trigger (sync from master)

Author: fdcastel

.github/workflows/release.yml

@@ -4,6 +4,7 @@ on:
   push:
     tags:
       - 'v[0-9]+.[0-9]+.[0-9]+*'
+  workflow_dispatch:  # allows manual retrigger via: gh workflow run Release --ref v<tag>
 
 permissions:
   contents: write