Fix command in README (#129)
Fix command in README (#129)

Tried this command just now and the backslashes resulted in this error if you directly copy/paste the command:

```zcain@zcain:~/ml-testing-accelerators$ gcloud beta secrets add-iam-policy-binding sendgrid-api-key \ --role roles/secretmanager.secretAccessor \ --member serviceAccount:xl-ml-test@appspot.gserviceaccount.com
ERROR: (gcloud.beta.secrets.add-iam-policy-binding) unrecognized arguments:
   --role
  roles/secretmanager.secretAccessor
   --member
  serviceAccount:xl-ml-test@appspot.gserviceaccount.com
  To search the help text of gcloud commands, run:
  gcloud help -- SEARCH_TERMS
```

Tried the 3 new commands and they work
GoogleCloudPlatform/ml-testing-accelerators,GoogleCloudPlatform/ml-testing-accelerators