Bump version to 2.13.0 (#1606)

Author: MasterOdin

CHANGELOG.md

@@ -1,5 +1,18 @@
 # Changelog
 
+## Version 2.13.0
+
+*April 22, 2022**
+
+* __Drop support for ruby 2.5__
+* Bump rouge from 3.27.0 to 3.28.0
+* Formally support ruby 3.1
+* Bump nokogiri from 1.12.5 to 1.13.3
+* Build docker images for multiple architectures (e.g. `aarch64`)
+* Remove `VOLUME` declaration from Dockerfile (thanks @aemengo)
+
+The security vulnerabilities reported against recent versions of nokogiri should not affect slate users with a regular setup.
+
 ## Version 2.12.0
 
 *November 04, 2021*