Remove CI build badge from package readme

It's not very relevant to the specific package version whether the CI build is green or not at the moment :)

Author: kzu

src/WebSocketPipe/readme.md

@@ -1,7 +1,6 @@
 [![Version](https://img.shields.io/nuget/vpre/WebSocketPipe.svg?color=royalblue)](https://www.nuget.org/packages/WebSocketPipe)
 [![Downloads](https://img.shields.io/nuget/dt/WebSocketPipe.svg?color=green)](https://www.nuget.org/packages/WebSocketPipe)
 [![License](https://img.shields.io/github/license/devlooped/WebSocketPipe.svg?color=blue)](https://github.com/devlooped/WebSocketPipe/blob/main/license.txt)
-[![Build](https://github.com/devlooped/WebSocketPipe/workflows/build/badge.svg?branch=main)](https://github.com/devlooped/WebSocketPipe/actions)
 
 # Usage