docs: add comment to the v1.12.0 issue

-e
Signed-off-by: machichima <[email protected]>

Author: machichima

plugins/flytekit-airflow/setup.py

@@ -7,6 +7,7 @@
 plugin_requires = [
     "apache-airflow<3.0.0",
     "apache-airflow-providers-google<12.0.0",
+    # NOTE: ref https://github.com/googleapis/python-spanner-sqlalchemy/issues/682
     "sqlalchemy-spanner!=1.12.0",
     "flytekit>1.10.7",
     "flyteidl>1.10.7",