Bump NSubstitute from 4.3.0 to 4.4.0

Bumps NSubstitute from 4.3.0 to 4.4.0.

---
updated-dependencies:
- dependency-name: NSubstitute
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

DNN Platform/Tests/DotNetNuke.Tests.Integration/packages.config

@@ -9,7 +9,7 @@
   <package id="Microsoft.NETFramework.ReferenceAssemblies.net472" version="1.0.2" targetFramework="net472" developmentDependency="true" />
   <package id="Moq" version="4.2.1502.0911" targetFramework="net45" />
   <package id="Newtonsoft.Json" version="10.0.3" targetFramework="net45" />
-  <package id="NSubstitute" version="4.3.0" targetFramework="net472" />
+  <package id="NSubstitute" version="4.4.0" targetFramework="net472" />
   <package id="NUnit" version="3.13.3" targetFramework="net472" />
   <package id="NUnit3TestAdapter" version="4.2.1" targetFramework="net472" />
   <package id="PetaPoco.Compiled" version="6.0.524" targetFramework="net472" />