Bump pip-tools from 6.3.0 to 6.4.0

Bumps [pip-tools](https://github.com/jazzband/pip-tools) from 6.3.0 to 6.4.0.
- [Release notes](https://github.com/jazzband/pip-tools/releases)
- [Changelog](https://github.com/jazzband/pip-tools/blob/master/CHANGELOG.md)
- [Commits](https://github.com/jazzband/pip-tools/compare/6.3.0...6.4.0)

---
updated-dependencies:
- dependency-name: pip-tools
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements/dev.txt

@@ -68,7 +68,7 @@ pallets-sphinx-themes==2.0.1
     # via -r requirements/docs.in
 pep517==0.11.0
     # via pip-tools
-pip-tools==6.3.0
+pip-tools==6.4.0
     # via -r requirements/dev.in
 platformdirs==2.4.0
     # via virtualenv