Update CHANGELOG.md (#50)

Author: dgaley

CHANGELOG.md

@@ -23,4 +23,7 @@
 * Remove caching of product ID lookups from DigiCert account  
 
 ### 2.2.0  
-* Add support for duplicating certs
+* Add support for duplicating certs
+
+### 2.2.1  
+* Properly mark 'needs_approval' status as Pending rather than Failed