build(deps): (deps): bump apispec from 6.3.1 to 6.4.0

Bumps [apispec](https://github.com/marshmallow-code/apispec) from 6.3.1 to 6.4.0.
- [Changelog](https://github.com/marshmallow-code/apispec/blob/dev/CHANGELOG.rst)
- [Commits](marshmallow-code/apispec@6.3.1...6.4.0)

---
updated-dependencies:
- dependency-name: apispec
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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