Upgrade IESI to 4.0.4 for having a bumped file version. (nhibernate#1598)

Author: fredericDelaporte

src/NHibernate/NHibernate.csproj

@@ -40,7 +40,7 @@
       <PrivateAssets>All</PrivateAssets>
     </PackageReference>
     <PackageReference Include="Antlr3.Runtime" Version="[3.5.1, 4.0)" />
-    <PackageReference Include="Iesi.Collections" Version="[4.0.3, 5.0)" />
+    <PackageReference Include="Iesi.Collections" Version="[4.0.4, 5.0)" />
     <PackageReference Include="Remotion.Linq" Version="[2.1.2, 3.0)" />
     <PackageReference Include="Remotion.Linq.EagerFetching" Version="[2.1.0, 3.0)" />
   </ItemGroup>