Added Better Code badge

Author: arbitrarybytes

README.md

@@ -3,3 +3,5 @@
 A .NET Standard 2.0 library consisting of a ton of very useful C# extension methods.
 
 [![Build status](https://ci.appveyor.com/api/projects/status/5i2gmikvtr3fiyw9/branch/master?svg=true)](https://ci.appveyor.com/project/arbitrarybytes/arbitrary-extensions/branch/master)
+
+[![BCH compliance](https://bettercodehub.com/edge/badge/arbitrarybytes/arbitrary-extensions?branch=master)](https://bettercodehub.com/)