Bump mysql2 from 0.4.10 to 0.5.0

Bumps [mysql2](https://github.com/brianmario/mysql2) from 0.4.10 to 0.5.0.
- [Release notes](https://github.com/brianmario/mysql2/releases)
- [Changelog](https://github.com/brianmario/mysql2/blob/master/CHANGELOG.md)
- [Commits](brianmario/mysql2@0.4.10...0.5.0)

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

Gemfile.lock

@@ -78,7 +78,7 @@ GEM
     mini_mime (1.0.0)
     mini_portile2 (2.3.0)
     minitest (5.11.3)
-    mysql2 (0.4.10)
+    mysql2 (0.5.0)
     nio4r (2.2.0)
     nokogiri (1.8.2)
       mini_portile2 (~> 2.3.0)