Update npgsql to 6.0.1

Author: mfussenegger

tests/client_tests/stock_npgsql/stock_npgsql.csproj

@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Npgsql" Version="5.0.2" />
+    <PackageReference Include="Npgsql" Version="6.0.1" />
   </ItemGroup>
 
 </Project>