bump to v7.3.0

[mr-tz]

Release checklist

• Ensure all milestoned issues/PRs are addressed, or reassign to a new milestone.
• Add the don't merge label to all PRs that are close to be ready to merge (or merge them if they are ready) in capa and capa-rules.
• Ensure the CI workflow succeeds in master.
• Ensure that python scripts/lint.py rules/ --thorough succeeds (only missing examples offenses are allowed in the nursery). You can manually trigger a thorough lint in CI via the "Run workflow" option.
• Review changes
  • capa https://github.com/mandiant/capa/compare/\<last-release>...master
  • capa-rules https://github.com/mandiant/capa-rules/compare/\...master
• Update CHANGELOG.md
  • Do not forget to add a nice introduction thanking contributors
  • Remember that we need a major release if we introduce breaking changes
  • Sections: see template below
  • Update Raw diffs links
  • Create placeholder for master (unreleased) section
• Update capa/version.py
• Create a PR with the updated CHANGELOG.md and capa/version.py. Copy this checklist in the PR description.
• After PR review, merge the PR and create the release in GH using text from the CHANGELOG.md.
• Verify GH actions
  • upload artifacts
  • publish to PyPI
  • create tag in capa rules
  • create release in capa rules
• Spread the word
• Update internal service

closes #2358

[mike-hunhoff]

🚀