Update cloud.json

Changed Saucelabs account 

http://premcompro:9a1a8562-d650-46dc-b8ea-8203df8a646e@ondemand.saucelabs.com:80/wd/hub
With 
http://premranjan12:a06b2af9-43c9-4e07-832a-21dfd7f26576@ondemand.saucelabs.com:80/wd/hub