Update changelog for 0.4.5-1 release

debian/changelog

+ruby-mysql2 (0.4.5-1) unstable; urgency=medium
+
+  * Team upload.
+  * New upstream version 0.4.5
+  * Switch to default-*mysql* (Closes: #845907)
+  * Work around mariadb grant issue
+  * Bump debhelper compat level to 10
+
+ -- Christian Hofstaedtler <zeha@debian.org>  Mon, 19 Dec 2016 00:40:04 +0000
+
 ruby-mysql2 (0.4.4-1) unstable; urgency=medium
 
   * Team upload