Include doc-only commit in provider commit history (apache#43543)

When we generated list of commits for provider's documentation, we
only checked for commits from the source folders of the providers,
however there were some commits that only changed documentation for
the provider and such commits were not included.

This PR adds documentation folder to be used while checkign for
the commit list, and next time when documentation will be generated
for providers, the doc-only commits should also be included for
all historical versions of providers.

dev/breeze/src/airflow_breeze/prepare_providers/provider_documentation.py

@@ -320,6 +320,7 @@ def _get_all_changes_for_package(
     providers_folder_paths = [
         provider_details.source_provider_package_path,
         provider_details.old_source_provider_package_path,
+        provider_details.documentation_provider_package_path,
     ]
     if not reapply_templates_only and result.returncode == 0:
         if get_verbose():