TagBot,yml: trigger doc deployment

try to trigger doc deployment by adding DOCUMENTER_KEY
(see https://github.com/orgs/community/discussions/27028)

ref #247

Author: alyst

.github/workflows/TagBot.yml

@@ -17,3 +17,4 @@ jobs:
       - uses: JuliaRegistries/TagBot@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
+          ssh: ${{ secrets.DOCUMENTER_KEY }}