Allow github actions to be triggered manually

Author: lucko

.github/workflows/build.yml

@@ -9,6 +9,7 @@ on:
   pull_request:
     branches:
       - 'master'
+  workflow_dispatch:
 
 env:
   REGISTRY: ghcr.io
@@ -53,4 +54,4 @@ jobs:
           platforms: linux/amd64,linux/arm64
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
+          labels: ${{ steps.meta.outputs.labels }}