fix: samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools/Org.OpenAPITools.csproj to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DOTNET-SYSTEMTEXTENCODINGSWEB-1253267

Author: snyk-bot

samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools/Org.OpenAPITools.csproj

@@ -23,7 +23,7 @@
   <ItemGroup>
     <PackageReference Include="CompareNETObjects" Version="4.83.0" />
     <PackageReference Include="Microsoft.Extensions.Http" Version="5.0.0" />
-    <PackageReference Include="Microsoft.Extensions.Hosting" Version="5.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Hosting" Version="6.0.0" />
     <PackageReference Include="Microsoft.Extensions.Http.Polly" Version="5.0.1" />
     <PackageReference Include="System.Threading.Channels" Version="8.0.0" />
     <PackageReference Include="System.ComponentModel.Annotations" Version="5.0.0" />