docs: Document bump version workflow (#1329)

src/docs/python-dependencies.mdx

@@ -13,7 +13,7 @@ data if they turn out to be malicious.
 
 Any new dependency needs to be thoroughly reviewed and approved by [owners-python-build](https://github.com/orgs/getsentry/teams/owners-python-build/members). This group is already automatically tagged in your PR to `sentry` or `getsentry` as soon as you edit relevant files. For other repos you might need to do it manually.
 
-To add or update a dependency:
+To add or manually update a dependency:
 
 1. Clone https://github.com/getsentry/pypi/.
 2. `cd` into your clone and run `python3 -m add_pkg PKGNAME` (or `python3 -m add_pkg PKGNAME==PKGVERSION` if you want a version other than the latest).
@@ -24,6 +24,13 @@ To add or update a dependency:
 7. Commit your changes (which should consist of changes to both one of the `requirements` files and its corresponding lockfile) to a branch and open a PR in the relevant repo. If it's not obvious, explain why you're adding or updating the dependency. Tag `owners-python-build` if they haven't already been auto-tagged.
 8. Merge your PR, pull `master`, and run `make install-py-dev`.
 
+To update a dependency using GitHub Actions:
+
+1. Go to https://github.com/getsentry/sentry/actions/workflows/bump-version.yml.
+2. Click the **Run workflow** dropdown.
+3. Fill in your package name and version.
+4. Click the **Run workflow** button.
+
 ## Depending on forks
 
 If you need to make modifications to a dependency and need to deploy the result