chore: Update dependencies.properties to use gax's version (#1792)

Author: lqiu96

gax-java/dependencies.properties

@@ -16,7 +16,7 @@ version.gax_grpc=2.29.1-SNAPSHOT
 # {x-version-update-start:gax:current}
 version.gax_bom=2.29.1-SNAPSHOT
 # {x-version-update-end}
-# {x-version-update-start:gax-httpjson:current}
+# {x-version-update-start:gax:current}
 version.gax_httpjson=2.29.1-SNAPSHOT
 # {x-version-update-end}