message: change main branch to feature/v4  in js sdk
diff: },
  "azure-sdk-for-js": {
  "integrationRepository": "AzureSDKAutomation/azure-sdk-for-js",
  - "mainRepository": "Azure/azure-sdk-for-js"
  + "mainRepository": "Azure/azure-sdk-for-js",
  + "mainBranch": "feature/v4"
  },
  "azure-sdk-for-net": {
  "integrationRepository": "AzureSDKAutomation/azure-sdk-for-net",
  