feat: add option to upsert to skip update if the row already exists and no values would be changed

[joeflateau]

Description of change

This change adds an option to upsert methods that instructs postgresql to skip the update if the update would not change any of a row's values. Without this, postgres will write every row to disk for each row that is upserted even if nothing has actually changed.

Pull-Request Checklist

• Code is up-to-date with the master branch
• npm run lint passes with this change
• npm run test passes with this change
• This pull request links relevant issues as Fixes #0000
• There are new or updated unit tests validating the change
• Documentation has been updated to reflect this change
• The new commits follow conventions explained in CONTRIBUTING.md

[joeflateau]

thank you

[pleerock]

thanks for another improvement :)