Fixed Publish parameter not working when updating existing function (#138)

Author: StefanoDalpiaz

lib/main.js

@@ -322,7 +322,7 @@ Lambda.prototype._uploadExisting = function(lambda, params, cb) {
   return lambda.updateFunctionCode({
     'FunctionName': params.FunctionName,
     'ZipFile': params.Code.ZipFile,
-    'Publish': params.publish
+    'Publish': params.Publish
   }, function(err, data) {
     if(err) {
       return cb(err, data);