add Francisco Correia to credits

Author: izelnakri

README.md

@@ -507,6 +507,7 @@ Many thanks to:
 - [Attila Szabo](https://github.com/szaboat) - Made %Version[:inserted_at] accept different ecto datetime options
 - [Rafael Scheffer](https://github.com/rschef) - Built PaperTrail.Serializer that unifies %Version{} serialization
 - [Kian Meng Ang](https://github.com/kianmeng) - Improved documentation
+- [Francisco Correia](https://github.com/fv316) - Made PaperTrail transaction keys and ecto transactions more customizable
 - [Izel Nakri](https://github.com/izelnakri) - The Originator of this library. See what I did there ;)
 
 Additional thanks to: