Add .NET 8 and 9 badges to README for multi-targeting visibility

Author: ANcpLua

README.md

@@ -1,5 +1,5 @@
 [![codecov](https://codecov.io/gh/ANcpLua/SWEN3.Paperless.RabbitMq/branch/main/graph/badge.svg?token=lgxIXBnFrn)](https://codecov.io/gh/ANcpLua/SWEN3.Paperless.RabbitMq)
-[![.NET 10](https://img.shields.io/badge/.NET-10.0-7C3AED)](https://dotnet.microsoft.com/download/dotnet/10.0)
+[![.NET 10](https://img.shields.io/badge/.NET-10.0-7C3AED)](https://dotnet.microsoft.com/download/dotnet/10.0)[![.NET 9](https://img.shields.io/badge/-9.0-6366F1)](https://dotnet.microsoft.com/download/dotnet/9.0)[![.NET 8](https://img.shields.io/badge/-8.0-512BD4)](https://dotnet.microsoft.com/download/dotnet/8.0)
 [![NuGet](https://img.shields.io/nuget/v/SWEN3.Paperless.RabbitMq?label=NuGet&color=0891B2)](https://www.nuget.org/packages/SWEN3.Paperless.RabbitMq/)
 [![License](https://img.shields.io/badge/License-MIT-blue.svg)](https://github.com/ANcpLua/SWEN3.Paperless.RabbitMq/blob/main/LICENSE)