Add GH spell checking action to this repo

[monde]

In triaging #1977 it was suggested we implement some sort of spell checking on our code (above and beyond VSCode spell check and code reviews). It will be easy to add the GH spell checking action to the ci.yml workflow and the get this check easily.

https://github.com/check-spelling

[duytiennguyen-okta]

OKTA internal reference https://oktainc.atlassian.net/browse/OKTA-724381