Update version to 2.3.0

Author: sjanuary

README.md

@@ -287,9 +287,10 @@ This project uses a semver-parsable X.0.Z version number for releases, where X i
 Non-release versions of this project (for example on github.com/RuntimeTools/SwiftMetrics) will use semver-parsable X.0.Z-dev.B version numbers, where X.0.Z is the last release with Z incremented and B is an integer. For further information on the development process go to the  [SwiftMetrics wiki][1]: [Developing](https://github.com/RuntimeTools/SwiftMetrics/wiki/Developing).
 
 ## Version
-2.2.1
+2.3.0
 
 ## Release History
+`2.3.0` - Support Swift 4.1 
 `2.2.1` - Minor dependency version change  
 `2.2.0` - New summary tab in SwiftMetrics dashboard  
 `2.1.0` - Remove KituraRequest dependency and switch to SwiftyRequest