I want to open demo app using appium (in ios simulator using X code)
You are referring a .swift file instead of .app file. Try writing this
.swift
.app
"appium:app": "/Users/pritwindersingh/Library/Developer/Xcode/DerivedData/WebDriverAgent-bpndfqzifmteusepnbmywejsnvgw/Build/Products/Debug-iphonesimulator/IntegrationApp.app"