Update autoware.repos

Co-authored-by: M. Fatih Cırıt <xmfcx@users.noreply.github.com>

Author: youtalk

autoware.repos

@@ -38,7 +38,7 @@ repositories:
     type: git
     url: https://github.com/autowarefoundation/autoware.universe.git
     version: main
-  universe/external/tier4_ad_api_adaptor:
+  universe/external/tier4_ad_api_adaptor: # TODO(TIER IV): Migrate to AD API and remove this repository entry.
     type: git
     url: https://github.com/tier4/tier4_ad_api_adaptor.git
     version: tier4/universe