chore: update sdk version in readme

Signed-off-by: Todd Baert <[email protected]>

Author: toddbaert

src/OpenFeature.Contrib.Providers.Flagd/README.md

@@ -6,7 +6,7 @@ The flagd Flag provider allows you to connect to your flagd instance.
 
 ## Requirements
 
-- open-feature/dotnet-sdk v1.5.0 > v2.0.0
+- open-feature/dotnet-sdk v2.0.0 > v3.0.0
 
 ## Install dependencies