Update documentation for list item update types

[JoshuaSHenderson]

Updated -UpdateType to reflect behaviors in version 3.1.0

Before creating a pull request, make sure that you have read the contribution file located at

https://github.com/pnp/powerShell/blob/dev/CONTRIBUTING.md

Type

• Bug Fix
• New Feature
• Sample?

Related Issues?

Fixes #X, partially fixes #Y, mentioned in #Z, etc.

What is in this Pull Request ?

Updated documentation for Set-PnPListItem to reflect actual behavior. If this is not the intended behavior, the Set-PnPListItem code may need investigated.
See examples below.

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OverwriteVersionHistory

This flag changed the version's modified date and appended the field that was modified. It also triggered a Power Automate flow

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SystemUpdate

This flag did not change the version's date or time and it appended the new field and value. No event was fired to trigger a Power Automate Flow

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• Please update this PR information accordingly. We use this as part of our release notes in monthly communications.
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[erwinvanhunen]

Thank you very much!