chore(deps): update dependency microsoft.featuremanagement to 4.0.0-preview4

Author: renovate[bot]

src/OpenFeature.Contrib.Providers.FeatureManagement/OpenFeature.Contrib.Providers.FeatureManagement.csproj

@@ -12,7 +12,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.FeatureManagement" Version="4.0.0-preview" />
+    <PackageReference Include="Microsoft.FeatureManagement" Version="4.0.0-preview4" />
   </ItemGroup>
 
 </Project>