Bump puppet-mysql to the latest 5.x version

We're seeing failures with puppet 5.5.7 in this module, lets see if the
latest 5.x series fixes this.

Change-Id: I8dd5cc828dbf1fcdb4f49473a6e9e0e57e54e6cf
Related-Bug: #1799757

Author: mwhahaha

Puppetfile

@@ -192,7 +192,7 @@ mod 'inifile',
 
 mod 'mysql',
   :git => 'https://github.com/puppetlabs/puppetlabs-mysql',
-  :ref => '5.2.1'
+  :ref => '5.4.0'
 
 mod 'postgresql',
   :git => 'https://github.com/puppetlabs/puppetlabs-postgresql',