Update changelog to include deprecations

[dzhavat]

Documentation Related To Component:

CHANGELOG

Please check those that apply

• typo
• documentation doesn't exist
• documentation needs clarification
• error(s) in example
• needs example

Description Of The Issue

v6.4.0 introduced some deprecations but only one of them is in the changelog. And even that one is kind of buried in the bug fixes.

It'd be helpful if all deprecations were in there preferably in a separate section so people are aware of them.

[BioPhoton]

@dzhavat i really like the idea. IMHO conventional changelog is used and there is the option to create/extend the topics.

@cartant could you please give some feedback here. 🙏🙏🙏

[cartant]

Related (and on my TODO list) #4776

[cartant]

See also #4776 (comment)

[benlesh]

I don't think we have the bandwidth to do this in an automated way. It's a good idea, but we're going to have to stick to what we have for now.