Update CONTRIBUTING.md

Author: maryamariyan

CONTRIBUTING.md

@@ -23,7 +23,7 @@ Before you start, make sure you have the following software installed on your ma
 
 * Node.js ([v18.17.0 LTS](https://nodejs.org/en/blog/release/v18.17.0) is recommended).
 * Npm (The version shipped with node is fine)
-* .NET 8.0 SDK (dotnet should be on your path)
+* .NET 7.0 SDK (dotnet should be on your path)
 
 Once you have these installed, you can proceed to clone the vscode-csharp repository: