Run the docs workflow when pushing a tag

* The run when pushing a commit bumping the concurrent-ruby version fails
  as the workflow relies on the tag to exist, but the tag is created
  later in the release process.
  So just re-run this workflow automatically when the tag is pushed.

Author: eregon

.github/workflows/docs.yml

@@ -2,6 +2,7 @@ name: Publish Docs to GitHub Pages
 on:
   push:
     branches: [master]
+    tags: ['v*']
   workflow_dispatch:
 
 permissions: