add new version

Author: sokil

CHANGELOG.md

@@ -1,7 +1,6 @@
 ## 0.5.3 (2019-05-06)
   * UniversalAdId added due to VAST 4.0 specification. UniversalAdId required in response beginning with VAST 4.0 (paragraph 3.7.1)
-  
-https://iabtechlab.com/wp-content/uploads/2018/11/VAST4.1-final-Nov-8-2018.pdf
+
 ## 0.5.2 (2019-03-23)
   * Add offset to progress event tracking. See specification 2.3.2.3 "Progress Event".