FIX Added the state changed checks and bubble up event

[josephlewisnz]

Note that this should not cause regressions for:

• Changes should not be tracked until a tag is added #125
• TagField triggers edit form change state when there are no changes #247

Issue

• Tag field change does not trigger change state #260

[josephlewisnz]

I tried to keep the PR inline as close to the branch 3
https://github.com/silverstripe/silverstripe-tagfield/pull/251/files

This branch (2) is using older version of react + node.
I didn't upgrade them so the there are slight changes in the approach

[GuySartorelli]

Thank you for submitting this PR.

In order for us to release this, it needs to be targetting the correct branch. The 2 branch would be used if we were to release this in a new minor release, but we aren't making new minor releases for the 2.x release line.
Please retarget this PR to the 2.11 branch, and reset your commits afterwards if necessary.

[josephlewisnz]

Thanks @GuySartorelli - Just running through the reset steps

[josephlewisnz]

@GuySartorelli I believe I have done that correctly..

[GuySartorelli]

Awesome, thank you. Looks correct to me. Someone will review this as time permits.

[sabina-talipova]

Looks good to me.
Test locally, all works perfect.