Update greeter_client.js (#25802 An error occurred )

ReferenceError: parseArgs is not defined

examples/node/static_codegen/greeter_client.js

@@ -16,6 +16,7 @@
  *
  */
 
+var parseArgs = require('minimist');
 var messages = require('./helloworld_pb');
 var services = require('./helloworld_grpc_pb');