chore: fix update MD links (#695)

Co-authored-by: Bharath KKB <bharathkrishnakb@gmail.com>
Co-authored-by: Imran Nayer <imrannayer@google.com>

Author: 3 people

README.md

@@ -23,7 +23,10 @@ The current version is 20.X. The following guides are available to assist with u
 - [10.X -> 11.0](./docs/upgrading_to_sql_db_11.0.0.md)
 - [11.X -> 12.0](./docs/upgrading_to_sql_db_12.0.0.md)
 - [19.X -> 20.0](./docs/upgrading_to_sql_db_20.0.0.md)
-- [20.X -> 21.0](./docs/upgrading_to_sql_db_21.0.0.md)
+- [20.X -> 21.0](./docs/upgrading_to_sql_db_21.0.md)
+- [21.X -> 22.0](./docs/upgrading_to_sql_db_22.0.md)
+- [22.X -> 23.0](./docs/upgrading_to_sql_db_23.0.md)
+- [23.X -> 24.0](./docs/upgrading_to_sql_db_24.0.md)
 
 ## Root module