build(deps): bump actix-files from 0.6.2 to 0.6.4

Bumps [actix-files](https://github.com/actix/actix-web) from 0.6.2 to 0.6.4.
- [Release notes](https://github.com/actix/actix-web/releases)
- [Changelog](https://github.com/actix/actix-web/blob/v0.6.4/CHANGES.md)
- [Commits](actix/actix-web@v0.6.2...v0.6.4)

---
updated-dependencies:
- dependency-name: actix-files
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>