chore(python): include docs/UPGRADING.md in docs/index.rst if it exists

synthtool/gcp/common.py

@@ -258,6 +258,10 @@ def py_library(self, **kwargs) -> Path:
         ):
             self.excludes += ["docs/index.rst"]
 
+        # Add kwargs to signal that UPGRADING.md should be included in docs/index.rst if it exists
+        if Path("docs/UPGRADING.md").exists():
+            kwargs["include_uprading_doc"] = True
+
         # Assume the python-docs-samples Dockerfile is used for samples by default
         if "custom_samples_dockerfile" not in kwargs:
             kwargs["custom_samples_dockerfile"] = False

synthtool/gcp/templates/python_library/docs/index.rst

@@ -14,23 +14,24 @@ API Reference
     {{ version }}/services
     {{ version }}/types
 {% endfor %}
-{%- if migration_guide_version %}
+{% if include_uprading_doc %}
 Migration Guide
 ---------------
 
-See the guide below for instructions on migrating to the {{ migration_guide_version }} release of this library.
+See the guide below for instructions on migrating to the latest version.
 
 .. toctree::
     :maxdepth: 2
 
-    UPGRADING
+    UPGRADING
+
 {% endif %}
 Changelog
 ---------
 
 For a list of all ``{{ metadata['repo']['distribution_name'] }}`` releases:
 
 .. toctree::
-   :maxdepth: 2
+    :maxdepth: 2
 
-   changelog
+    changelog