Update TagBot.yml

Author: kibaekkim

.github/workflows/TagBot.yml

@@ -1,10 +1,12 @@
 name: TagBot
 on:
-  issue_comment:  # THIS BIT IS NEW
+  issue_comment:
     types:
       - created
+  workflow_dispatch:
 jobs:
   TagBot:
+    if: github.event_name == 'workflow_dispatch' || github.actor == 'JuliaTagBot'
     runs-on: ubuntu-latest
     steps:
       - uses: JuliaRegistries/TagBot@v1