ci: Use meltano/commitizen-version-bump (#924)

* ci: `Use meltano/commitizen-version-bump`

To customize how Commitizen performs our version bump, Meltano and the SDK will now use https://github.com/meltano/commitizen-version-bump. It will be installed and used by commitizen-action in the version_bump GitHub workflow.

All of the customizations used by the SDK should continue to work unchanged: meltano/commitizen-version-bump@d049f8e

* Add `commitizen-version-bump` to dev deps

.github/workflows/version_bump.yml

@@ -55,6 +55,7 @@ jobs:
         push: "false"
         changelog: "true"
         github_token: ${{ secrets.GITHUB_TOKEN }}
+        extra_requirements: 'git+https://github.com/meltano/commitizen-version-bump@main'
         changelog_increment_filename: _changelog_fragment.md
 
     - name: Draft Release