Update dependency NSubstitute to v4.4.0

Author: renovate[bot]

src/NHibernate.Test/NHibernate.Test.csproj

@@ -59,7 +59,7 @@
     <PackageReference Include="Microsoft.Data.SqlClient" Version="3.0.0" />
     <PackageReference Include="System.Data.SQLite.Core" Version="1.0.115.5" />
     <PackageReference Include="System.Linq.Dynamic.Core" Version="1.2.12" />
-    <PackageReference Include="NSubstitute" Version="4.2.2" />
+    <PackageReference Include="NSubstitute" Version="4.4.0" />
     <PackageReference Include="NUnit" Version="3.13.2" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.2.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />