Update Nancy version (#3771)

frameworks/CSharp/nancy/src/NancyBenchmark.csproj

@@ -20,7 +20,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Nancy" Version="2.0.0-clinteastwood" />
+    <PackageReference Include="Nancy" Version="2.0.0-pre1909" />
     <PackageReference Include="MySqlConnector" Version="0.40.3" />
     <PackageReference Include="Dapper" Version="1.50.4" />
   </ItemGroup>

frameworks/CSharp/nancy/src/NuGet.config

@@ -4,5 +4,6 @@
     <clear />
     <add key="NuGet" value="https://api.nuget.org/v3/index.json" />
     <add key="aspnetcore" value="https://dotnet.myget.org/F/aspnetcore-dev/api/v3/index.json" />
+    <add key="Nancy" value="https://www.myget.org/F/nancyfx/api/v3/index.json" />
   </packageSources>
 </configuration>