Add changelog for 6.1.0

[consideRatio]

I propose that we cut a release now with bugfixes, a performance improvement, and the unlisted_choice functionality part of profile_lists -> profile_options.

• Closes Release planning for 6.1.0 #767

If approved by monday next week, I'll cut a release then.

[GeorgianaElena]

@consideRatio, I think we might want to also fix this #758 as part of a new release. A workaround we've used for this was https://github.com/2i2c-org/infrastructure/pull/2865/files.

[consideRatio]

Ah, I agree!

[yuvipanda]

I've resolved the merge conflicts, and want to appreciate you doing all the release prep work, @consideRatio! I'm happy to share some of the load if you so choose. But this is ready to go now from my perspective.

[consideRatio]

I've not pushed on this as i felt we absolutely need a note in the changelog to help users remediate the consequences of the bug as well - this is the place to make such note.

I plan to test a script by Min tomorrow helping with that, possibly make a smaller tweak, and then link to it from the changelog.

[shaneknapp]

@consideRatio thanks for the update!

[yuvipanda]

LGTM