Bump puma from 6.3.1 to 6.4.0

Bumps [puma](https://github.com/puma/puma) from 6.3.1 to 6.4.0.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](https://github.com/puma/puma/compare/v6.3.1...v6.4.0)

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

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

Gemfile.lock

@@ -288,7 +288,7 @@ GEM
     pry-rails (0.3.9)
       pry (>= 0.10.4)
     public_suffix (5.0.3)
-    puma (6.3.1)
+    puma (6.4.0)
       nio4r (~> 2.0)
     pundit (2.3.1)
       activesupport (>= 3.0.0)