Update release notes

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

Author: llucax

RELEASE_NOTES.md

@@ -32,6 +32,7 @@ But you might still need to adapt your code:
 - API projects now have a better grpcio/protobuf updates grouping in Dependabot, which should make upgrading easier, and plays nicer with the new `grpc-migration.yaml` workflow.
 - API projects should now use the new API-specific *Protect version branches* ruleset variant, which includes the required `Fix gRPC/protobuf runtime floors` check without affecting non-API Python projects.
 - Workflows using the `gh-action-dependabot-migrate` are upgraded to the latest version, which avoids unnecessary version iterations.
+- Add an `isort-migration.yaml` workflow that automatically reorders imports when Dependabot upgrades `isort`.
 
 ## Bug Fixes
 
@@ -44,6 +45,7 @@ But you might still need to adapt your code:
 - The issue template chooser (`config.yml`) no longer includes the `contact_links` section for private repositories, since GitHub Discussions are typically disabled for them.
 - Normalized the GitHub Action hashes for `gh-action-setup-git` and `gh-action-setup-python-with-deps` to point to the actual commit object, which is what Dependabot expects.
 - API projects now configure black with `extend-exclude = '^/submodules/'` so the formatting check doesn't descend into external git submodules that don't follow our formatting rules.
+- API projects now configure isort with `skip_glob = ["submodules/*"]` so the import-sorting check doesn't descend into external git submodules that don't follow our rules.
 - `CONTRIBUTING.md`
   * Fixed the nox example commands in  to use the correct `tests/` directory instead of the non-existent `test/` directory.
   * Fixed the wrong mention to PyPI publishing when releasing for private repositories.