ci: Add workflow_dispatch trigger to artifact.yml

Signed-off-by: 梦里不知身是客 <liang.tang.cx@gmail.com>

Author: unknowIfGuestInDream

.github/workflows/artifact.yml

@@ -11,6 +11,7 @@ on:
       - 'LICENSE'
       - '.gitignore'
       - 'images/**'
+  workflow_dispatch:      
 
 permissions:
   contents: read