Bump nunit from 4.3.0 to 4.3.1 (#1859)

Author: dependabot[bot]

UnitTests/UnitTests.csproj

@@ -26,7 +26,7 @@
     <PackageReference Include="AltCover" Version="9.0.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
-    <PackageReference Include="nunit" Version="4.3.0" />
+    <PackageReference Include="nunit" Version="4.3.1" />
     <PackageReference Include="NUnit.Analyzers" Version="4.4.0">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>