Update README for AGOL component publishing script

[frankhereford]

Associated issues

https://github.com/cityofaustin/atd-data-tech/issues/18672

Testing

Take a look at the updated README here, the diff here, and see if you like the changes. Everyone needs an editor, so please don't hesitate to ask for anything you think could be improved.

Thanks!

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Ship list

• [ ] ~Code reviewed~
• [ ] Product manager approved
• [ ] Product manager checked DB view dependencies
• [ ] Product manager added to QA test script if applicable