Fix TagBot workflow (#14)

* Add required TagBot permissions

* Add self-test trigger to TagBot workflow

* Adjust conditional

Author: omus

.github/workflows/TagBot.yml

@@ -4,10 +4,26 @@ on:
   issue_comment:
     types:
       - created
+  pull_request:
+    paths:
+      - ".github/workflows/TagBot.yml"
   workflow_dispatch:
+permissions:
+  actions: read
+  checks: read
+  contents: write
+  deployments: read
+  issues: read
+  discussions: read
+  packages: read
+  pages: read
+  pull-requests: read
+  repository-projects: read
+  security-events: read
+  statuses: read
 jobs:
   TagBot:
-    if: ${{ github.event_name == 'workflow_dispatch' || github.actor == 'JuliaTagBot' }}
+    if: ${{ github.event_name != 'issue_comment' || github.actor == 'JuliaTagBot' }}
     runs-on: ubuntu-latest
     steps:
       - uses: JuliaRegistries/TagBot@v1