Enable CI triggering by workflow_dispatch

https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#workflow_dispatch

Author: Goooler

.github/workflows/ci.yml

@@ -6,6 +6,8 @@ on:
   pull_request:
   push:
     branches: [main]
+  workflow_dispatch:
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true