docs: update version

Author: nancynh

docs/cmd/alloydb-auth-proxy.md

@@ -261,7 +261,7 @@ Third Party Licenses
   To view all licenses for third party dependencies used within this
   distribution please see:
 
-  https://storage.googleapis.com/alloydb-auth-proxy/v1.13.8/third_party/licenses.tar.gz 
+  https://storage.googleapis.com/alloydb-auth-proxy/v1.13.9/third_party/licenses.tar.gz 
 
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