Add pre-release badge to Readme.md (#132)

* Add pre-release badge

Co-authored-by: ITDancer139 <[email protected]>

README.md

@@ -2,7 +2,8 @@
 ⚗️ Sieve is a simple, clean, and extensible framework for .NET Core that **adds sorting, filtering, and pagination functionality out of the box**. 
 Most common use case would be for serving ASP.NET Core GET queries.
 
-[![NuGet Release](https://img.shields.io/nuget/v/Sieve.svg?style=flat-square)](https://www.nuget.org/packages/Sieve)
+[![NuGet Release](https://img.shields.io/nuget/v/Sieve?style=for-the-badge)](https://www.nuget.org/packages/Sieve)
+[![NuGet Pre-Release](https://img.shields.io/nuget/vpre/Sieve?style=for-the-badge)](https://www.nuget.org/packages/Sieve)
 
 [Get Sieve on nuget](https://www.nuget.org/packages/Sieve/)