fix miss spelling

[slowy07]

Thanks for stopping by to let us know something could be better!

PLEASE READ: If you have a support contract with Google, please create an issue in the support console instead of filing on GitHub. This will ensure a timely response.

Please run down the following list and make sure you've tried the usual "quick fixes":

• fix miss codespelling

If you are still having issues, please be sure to include as much information as possible:

Environment details

• OS type and version:
• Python version: python --version
• pip version: pip --version
• google-cloud-aiplatform version: pip show google-cloud-aiplatform

Steps to reproduce

1. search the misspelling
2. fixing the spelling

Code example

"""
credentials (Optional[google.auth.credentials.Credentials]): The
                authorization credentials to attach to requests. These
                credentials identify the applicatin to the service; if none
                are specified, the client will attempt to ascertain the
"""

to

"""
credentials (Optional[google.auth.credentials.Credentials]): The
                authorization credentials to attach to requests. These
                credentials identify the application to the service; if none
                are specified, the client will attempt to ascertain the
"""

Making sure to follow these steps will guarantee the quickest resolution possible.

Thanks!