Bump mysql2 from 0.5.2 to 0.5.3

Bumps [mysql2](https://github.com/brianmario/mysql2) from 0.5.2 to 0.5.3.
- [Release notes](https://github.com/brianmario/mysql2/releases)
- [Commits](https://github.com/brianmario/mysql2/compare/0.5.2...0.5.3)

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

Gemfile

@@ -23,7 +23,7 @@ gem 'jquery-ui-rails' , '~>5.0.5'
 # always possible on all platforms
 # Alternatively use --without <group> arguments to bundler to not install that group
 gem "sqlite3", group: :sqlite
-gem "mysql2", "~> 0.5.2", group: :mysql
+gem "mysql2", "~> 0.5.3", group: :mysql
 
 gem "RedCloth"
 gem "sanitize", "~> 5.1"

Gemfile.lock

@@ -134,7 +134,7 @@ GEM
     minitest (5.13.0)
     minitest-stub-const (0.6)
     mocha (1.11.2)
-    mysql2 (0.5.2)
+    mysql2 (0.5.3)
     nio4r (2.5.2)
     nokogiri (1.10.7)
       mini_portile2 (~> 2.4.0)
@@ -291,7 +291,7 @@ DEPENDENCIES
   listen
   minitest-stub-const
   mocha
-  mysql2 (~> 0.5.2)
+  mysql2 (~> 0.5.3)
   paperclip
   puma (~> 4.3)
   rack-mini-profiler