Change screenshot to format supported by nuget.org

Author: kzu

readme.md

@@ -9,7 +9,7 @@
 <!-- #content -->
 Pretty-print test results in TRX format.
 
-![Demo](https://github.com/devlooped/dotnet-trx/blob/main/assets/img/demo.png?raw=true)
+![Demo](https://raw.githubusercontent.com/devlooped/dotnet-trx/main/assets/img/demo.png)
 
 Typical usage: `dotnet test --logger trx; trx` (optionally with `--output`).