chore(deps): update dependency nunit to v4

Author: renovate[bot]

tests/TestableIO.System.IO.Abstractions.TestingHelpers.Tests/TestableIO.System.IO.Abstractions.TestingHelpers.Tests.csproj

@@ -34,7 +34,7 @@
     <PackageReference Include="GitHubActionsTestLogger" Version="2.3.3" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageReference Include="Moq" Version="4.20.70" />
-    <PackageReference Include="NUnit" Version="3.14.0" />
+    <PackageReference Include="NUnit" Version="4.0.1" />
     <PackageReference Include="NUnit.Analyzers" Version="3.10.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>

tests/TestableIO.System.IO.Abstractions.Wrappers.Tests/TestableIO.System.IO.Abstractions.Wrappers.Tests.csproj

@@ -19,7 +19,7 @@
     <PackageReference Include="GitHubActionsTestLogger" Version="2.3.3" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageReference Include="Moq" Version="4.20.70" />
-    <PackageReference Include="NUnit" Version="3.14.0" />
+    <PackageReference Include="NUnit" Version="4.0.1" />
     <PackageReference Include="NUnit.Analyzers" Version="3.10.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
     <PackageReference Include="Snapshooter.NUnit" Version="0.13.0" />