Added Change Log entry

Author: Stephen Martin

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## In Development
 * Change st2packs definition to a list, to support multiple st2packs containers (#166) (by @moonrail)
 * Enabled RBAC/LDAP configuration for OSS version, removed enterprise flags (#182) (by @hnanchahal)
+* Fixed datastore_crypto_key secret name for rules engine (#188) (by @lordpengwin)
 
 ## v0.52.0
 * Improve resource allocation and scheduling by adding resources requests cpu/memory values for st2 Pods (#179)