[release process] Robustify the version-bump PR

This just adds a little info about what will happen after a
version bump PR is merged.

.github/workflows/version-bump.yml

@@ -59,7 +59,13 @@ jobs:
 
           Tag v${{ steps.bump-all.outputs.NEW_VERSION_NUMBER }}
 
-          - Auto-generated by [create-pull-request][1]
+          Note: Merging this PR with trigger the following actions:
+            * The `main` branch will be tagged with `v${{ steps.bump-all.outputs.NEW_VERSION_NUMBER }}`
+            * A GitHub Release will be created for `v${{ steps.bump-all.outputs.NEW_VERSION_NUMBER }}`
+            * Version `${{ steps.bump-all.outputs.NEW_VERSION_NUMBER }}` of the gems will be pushed to rubygems.org
+            * Version `${{ steps.bump-all.outputs.NEW_VERSION_NUMBER }}` of the npm packages will be pushed to npmjs.com
+
+          - Auto-generated by [create-pull-request][1] via `.github/workflows/version-bump.yml`
 
           [1]: https://github.com/peter-evans/create-pull-request
         labels: |