Update changelog for 2.30.5-1pureos0 release

debian/changelog

+webkit2gtk (2.30.5-1pureos0) byzantium; urgency=high
+
+  * Release to byzantium
+
+ -- Alexander Mikhaylenko <alexander.mikhaylenko@puri.sm>  Wed, 17 Feb 2021 12:16:16 +0500
+
 webkit2gtk (2.30.5-1) unstable; urgency=high
 
   * New upstream release (Closes: #978042).