Bump puma from 3.9.1 to 3.11.3

Bumps [puma](https://github.com/puma/puma) from 3.9.1 to 3.11.3.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v3.9.1...v3.11.3)

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

Gemfile

@@ -15,7 +15,7 @@ gem 'jquery-rails'
 gem 'jquery-ui-rails'
 gem 'mysql2', '>= 0.3.18', '< 0.5'
 gem 'pg'
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 3.11'
 gem 'rails', '~> 5.1.1'
 gem 'rails-i18n'
 gem 'rails_bootstrap_navbar'

Gemfile.lock

@@ -167,7 +167,7 @@ GEM
     pry (0.11.3)
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
-    puma (3.9.1)
+    puma (3.11.3)
     rack (2.0.4)
     rack-protection (2.0.1)
       rack
@@ -308,7 +308,7 @@ DEPENDENCIES
   mysql2 (>= 0.3.18, < 0.5)
   pg
   pry
-  puma (~> 3.7)
+  puma (~> 3.11)
   rails (~> 5.1.1)
   rails-i18n
   rails_bootstrap_navbar