chore(deps): update dependency nsubstitute to 5.3.0 (#121)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Chris Pulman <[email protected]>

Author: renovate[bot]

Diff for: src/ReactiveMvvm.Tests/ReactiveMvvm.Tests.csproj

@@ -12,7 +12,7 @@
     </PackageReference>
     <PackageReference Include="FluentAssertions" Version="6.12.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
-    <PackageReference Include="NSubstitute" Version="5.1.0" />
+    <PackageReference Include="NSubstitute" Version="5.3.0" />
     <PackageReference Include="ReactiveUI.Testing" Version="20.2.45" />
     <PackageReference Include="xunit" Version="2.9.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">