Prepare 0.7.0 release

[garrison]

Remaining action items:

• Test all tutorial notebooks on a hardware backend
• Update authors in CITATION.bib
• Update version [sub]string in all files where it appears in the repository
  • .mergify.yml
  • pyproject.toml
  • .github/workflows/docs.yml
• move release notes to 0.7 directory
• merge everything except this PR on the 0.7 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 0.7.0 -m "Circuit Knitting Toolbox 0.7.0"
  5. git show (double/triple check the tag is on the correct branch)
  6. git push origin 0.7.0
• Wait for CI to finish. The release should then be available on GitHub and pypi.
• create the stable/0.7 branch
  1. start with same commit as above checked out
  2. git checkout -b stable/0.7
  3. git show (check before pushing)
  4. git push --set-upstream origin stable/0.7
• get docs to deploy from the new stable branch (should happen automatically at this point after CI runs both on the new stable branch and then on the gh-pages branch)
• move remaining 0.6.1 milestone items to 0.7.1 milestone and close 0.6.1 & 0.7.0 milestones

Previous release PR: #485

[coveralls]

Pull Request Test Coverage Report for Build 8740593666

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 95.438%

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Totals
Change from base Build 8728049092:	0.0%
Covered Lines:	3452
Relevant Lines:	3617

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💛 - Coveralls

[ibrahim-shehzad]

This PR looks good to merge to me, given that we are okay with holding off on #552 .

[caleb-johnson]

Looks good as usual. You might update your PR description to include a bullet for updating the version in pyproject.toml for the sake of completeness. Maybe somewhere around the 3rd item?

"Some of us" (me) might forget to bump that if it's not on the list 😎