Update NUnit and NUnit3TestAdapter package versions

Updated NUnit package from 4.3.1 to 4.3.2.
Updated NUnit3TestAdapter package from 4.6.0 to 5.0.0.
No changes to target framework, Moq, Microsoft.NET.Test.Sdk, or Edi.Captcha.csproj.

Author: EdiWang

src/Edi.Captcha.Tests/Edi.Captcha.Tests.csproj

@@ -4,9 +4,9 @@
     <IsPackable>false</IsPackable>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="NUnit" Version="4.3.1" />
+    <PackageReference Include="NUnit" Version="4.3.2" />
     <PackageReference Include="Moq" Version="4.20.72" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="5.0.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
   </ItemGroup>
   <ItemGroup>