Updates appveyor.yml to 1.13.3
Updates appveyor.yml to 1.13.3

Merchello/Merchello.Bazaar,ProNotion/Merchello,Merchello/Merchello,rasmusjp/Merchello,rasmusjp/Merchello,Merchello/Merchello,ProNotion/Merchello,rasmusjp/Merchello,Merchello/Merchello.Bazaar,Merchello/Merchello,Merchello/Merchello.Bazaar,clausjensen/Merchello,ProNotion/Merchello,clausjensen/Merchello,clausjensen/Merchello