change(docs): Add changelog entry for stable mining feature

[teor2345]

Motivation

We want to talk about stabilising mining RPCs in the changelog for the next release.

The mining part of the README also needs an update.

This is a follow-up to ticket #7361.

Review

This is a low priority documentation change. Technically it blocks the next release, but it should be merged long before then.

Reviewer Checklist

• Are the PR labels correct?
• Does the code do what the ticket and PR says?
  • Does it change concurrent code, unsafe code, or consensus rules?
• How do you know it works? Does it have tests?

[upbqdn]

I wonder if we should also mention that miners will still need to run zcashd for rewards distribution.

[teor2345]

I wonder if we should also mention that miners will still need to run zcashd for rewards distribution.

I think it depends on the mining software. Some of them make their own coinbase transactions that distribute rewards, or using their own miner address.

What do you think about commit 44a5f9f?
(The README needed an update for mining.)

We could copy some of that wording into the CHANGELOG?