Prepare 0.2.0 release

[garrison]

Creating this early so we can add to the checklist as we think of things. These are all things that should go in this final PR to prepare the release.

• Bump version number in all relevant places (right now, just pyproject.toml)
• Prepare "prelude" release note to highlight major features in this release (added as part of Final (0.2.0) cutting workflow #153)
• Check rendering of release notes; proofread them too
• Revisit release milestone. Move anything that isn't going to make it to a future milestone.
• Move all release notes to 0.2 directory (be sure to merge main into the current branch before doing this)
• Merge this PR. Wait for CI on main to turn green before continuing.
• Tag a release using git tag -a 0.2.0. Write "Circuit Knitting Toolbox 0.2.0" as the commit message. Be very careful to make sure this is attached to the correct commit. (I.e., run git pull before doing this, make sure you're on main, and run git show both before and after tagging it to make sure the tag ended up on the correct commit.) Then run git push origin 0.2.0, and watch as the release appears on GitHub and pypi.
• Close the release milestone (once all outstanding issues are closed or moved to the subsequent milestone)

Previous release PR: #129

[github-actions]

Pull Request Test Coverage Report for Build 5096563275

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 89.35%

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Totals
Change from base Build 5096504573:	0.0%
Covered Lines:	2324
Relevant Lines:	2601

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💛 - Coveralls

[caleb-johnson]

My release notes edits in #209 . I went ahead and merged since I verified it locally so many times. This should make it easier for you to final review.

[garrison]

Reno didn't like the merge commit, so I had to force push to get rid of it.