Update CHANGELOG

CHANGELOG

@@ -1,3 +1,8 @@
+0.5.2
+- Fix AES-CTR incremental updates. #287
+- Fixed PBKDF2 tests. #295
+- Fixed assertion check in PKCS7. #288
+
 0.5.1
 - Fixed PBKDF2 not taking key length parameter into account
 - Switch to Array<> in code