Prepare for 1.1.0 (tehplague#68)

* Prepare for 1.1.0

* Update Changelog.md

Author: Nyholm

Changelog.md

@@ -2,6 +2,15 @@
 
 This document will tell you what changes that has been made between versions.
 
+# Changes from 1.0.0 to 1.1.0
+
+* Support for Symfony 4
+* Dropped support for Symfony 2
+
+# Changes from 0.4.0 to 1.0.0
+
+* Support for Swift mailer 6. 
+
 # Changes from 0.3.x to 0.4.0
 
 * Removed the `mailgun.swift_transport.transport.class` parameter.