docs: adds CHANGELOG entry for laminas#104

Signed-off-by: Matthew Weier O'Phinney <[email protected]>

Author: weierophinney

CHANGELOG.md

@@ -22,7 +22,7 @@ All notable changes to this project will be documented in this file, in reverse
 
 ### Fixed
 
-- Nothing.
+- [#104](https://github.com/laminas/laminas-mail/pull/104) fixes an issue that occured when the `Sendmail` transport was configured with a `-f` option (From address). Prior to the fix, the option would be overwritten by the message `From` or `Sender` headers, which could lead to errors on systems where all mail must be sent from a specific address. The fixed behavior is to always honor the `-f` option, and ignore the `From` and `Sender` headers if it was provided to the transport.
 
 ## 2.12.1 - 2020-08-05