Update README.md

Author: rdeioris

README.md

@@ -30,7 +30,7 @@ Once the plugin is installed and enabled, you get access to the 'PythonConsole'
 
 All of the exposed engine features are under the 'unreal_engine' virtual module (it is completely coded in c into the plugin, so do not expect to run 'import unreal_engine' from a standard python shell)
 
-The currently supported Unreal Engine versions are 4.12, 4.13, 4.14, 4.15, 4.16, 4.17, 4.18, 4.19 and 4.20
+The currently supported Unreal Engine versions are 4.12, 4.13, 4.14, 4.15, 4.16, 4.17, 4.18, 4.19, 4.20 and 4.21
 
 We support official python.org releases as well as IntelPython and Anaconda distributions.