Prepare 0.7.1 release

[garrison]

If we merge this PR to main, we can tag 0.7.1 from main and fast-forward the stable/0.7 branch to the same commit. This will mean that #556 will be included in the patch release as well. If we don't want this, then we should backport #563 to stable/0.7 and tag the release from that branch instead.

Remaining action items (checklist for patchlevel release):

• Test all tutorial notebooks on a hardware backend
• Update version [sub]string in all files where it appears in the repository
  • pyproject.toml
• move release notes to 0.7 directory
• merge everything except this PR on the 0.7.1 milestone
• build docs locally; proofread the release notes
• merge this PR
• tag the release
  1. git checkout main
  2. git pull
  3. git show (verify it's the commit we want to tag)
  4. git tag -a 0.7.1 -m "Circuit Knitting Toolbox 0.7.1"
  5. git show (double/triple check the tag is on the correct branch)
  6. git push origin 0.7.1
• Wait for CI to finish. The release should then be available on GitHub and pypi.
• fast-forward the stable/0.7 to the same commit
  1. git checkout stable/0.7
  2. git merge --ff-only 0.7.1
• get docs to deploy (should happen automatically at this point after CI runs both on stable/0.7 and then on the gh-pages branch)
• move remaining 0.7.1 milestone items to 0.7.2 milestone and close 0.7.1 milestone

Previous release PR: #555

[coveralls]

Pull Request Test Coverage Report for Build 8835531657

Details

• 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 95.489%

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Totals
Change from base Build 8835377332:	0.0%
Covered Lines:	3493
Relevant Lines:	3658

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💛 - Coveralls

[garrison]

@caleb-johnson I know I claimed previously that this should be fixes instead of upgrade, but after previewing the release notes I actually think it makes even more sense to be other, i.e., under "other notes" rather than "bug fixes".

[caleb-johnson]

Looks great! Thanks