chore: prep v2.1.0 changelog

[rjan90]

I've prepared the v2.1.0 changelog in this PR. We have two options moving forward:

• If PR #195 gets reviewed/lands soon, we can use it to test the release automation triggered by a version bump.
• Otherwise, we can proceed with a manual release this time to unblock things and get the PDP update out to Calibnet and Mainnet.

[rjan90]

Otherwise, we can proceed with a manual release this time to unblock things and get the PDP update out to Calibnet and Mainnet.

I have gone for updating the version string in this PR here as well, so that I can get unblocked on shipping this PDP release to Mainnet.

[rvagg]

in terms of format I don't love this, it's a bit too verbose when I think of what I look for when I'm reviewing a changelog; it's not a bad idea to highlight the big deal ones and expand on them a bit, but some others are not relevant to downstream users - like the CI/CD stuff could just be done in one line as a mention cause only contributors care.

[rjan90]

like the CI/CD stuff could just be done in one line as a mention cause only contributors care.

Removed the CI/CD part in: 9635f5a