Corrected '0. Authentication' command

[juangascon]

Description

The command shown was 'google auth login' but it should be 'gcloud auth login'

Motivation and Context

The command was not correct.
It solves a possible block following the tutorial for newbies as me on GCP.
This change protects us from searching in internet how to install the 'google' command that does not exist.

How Has This Been Tested?

• Covered by existing integration testing
• Added integration testing to cover
• Tested locally
• Have not tested

Testing should not be necessary. It is a small change in the documentation. No code involved. It should pass or not the test as before the proposed change.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[edwarnicke]

@juangascon Could you add a signed off by line for DCO using

git commit -s --amend --no-edit;git push -f

[juangascon]

Done. As with PR #2251 :-)