Bump puma from 5.6.8 to 6.4.2

Bumps [puma](https://github.com/puma/puma) from 5.6.8 to 6.4.2.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v5.6.8...v6.4.2)

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

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

Gemfile

@@ -9,7 +9,7 @@ gem 'rails', '~> 6.1', '>= 6.1.3.1'
 # Use postgresql as the database for Active Record
 gem 'pg', '>= 0.18', '< 2.0'
 # Use Puma as the app server
-gem 'puma', '~> 5.6'
+gem 'puma', '~> 6.4'
 # Admin interface
 gem 'administrate', '~> 0.15'
 # JSON Web Tokens

Gemfile.lock

@@ -173,7 +173,7 @@ GEM
  racc
  pg (1.3.1)
  public_suffix (4.0.6)
- puma (5.6.8)
+ puma (6.4.2)
  nio4r (~> 2.0)
  racc (1.7.3)
  rack (2.2.9)
@@ -307,7 +307,7 @@ DEPENDENCIES
  ffaker
  jwt (~> 2.2)
  pg (>= 0.18, < 2.0)
- puma (~> 5.6)
+ puma (~> 6.4)
  rails (~> 6.1, >= 6.1.3.1)
  rails-controller-testing
  rspec-github