TagBot: use DOCUMENTER_KEY (#944)

Author: DilumAluthge

.github/workflows/TagBot.yml

@@ -2,10 +2,12 @@ name: TagBot
 on:
   schedule:
     - cron: 0 0 * * *
+  workflow_dispatch:
 jobs:
   TagBot:
     runs-on: ubuntu-latest
     steps:
       - uses: JuliaRegistries/TagBot@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
+          ssh: ${{ secrets.DOCUMENTER_KEY }}