Update changelog for 2.2.3-2 release

debian/changelog

+php-proxy-manager (2.2.3-2) unstable; urgency=medium
+
+  * Fix CamelCase in patch
+  * Remove obsolete fields Name, Contact from debian/upstream/metadata.
+  * Drop versioned dependencies satisfied in (old)stable
+  * Update standards version to 4.4.1, no changes needed.
+  * Set upstream metadata fields:
+    Bug-Database, Repository, Repository-Browse, Bug-Submit
+
+ -- David Prévot <taffit@debian.org>  Wed, 25 Dec 2019 07:37:22 +1100
+
 php-proxy-manager (2.2.3-1) unstable; urgency=medium
 
   * Track 2.2 branch