Fix ChangeLog whitespace errors and add entry for PR
PR is a change to the behaviour of the CMake files therefore should be
recorded in the Changelog.
@@ -13,6 +13,9 @@ Bugfix
* Fix the cert_write example to handle certificates signed with elliptic
curves as well as RSA. Fixes #777 found by dbedev.
+Changes
+ * Changed CMake defaults for IAR to treat all compiler warnings as errors.
+
= mbed TLS 2.10.0 branch released 2018-06-06
Features
