Revert "Bump bunit from 1.40.0 to 2.4.2 (#51)"

This reverts commit 1b6e3f5.

Author: arika0093

tests/Directory.Build.props

@@ -8,7 +8,7 @@
   <ItemGroup>
     <PackageReference Include="Shouldly" Version="4.*" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
-    <PackageReference Include="bunit" Version="2.4.2" />
+    <PackageReference Include="bunit" Version="1.*" />
     <PackageReference Include="xunit" Version="2.*" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.*">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>