Bump Microsoft.NET.Test.Sdk from 16.3.0 to 16.4.0 (#52)

Author: dependabot-preview[bot]

WebDriverManager.Tests/WebDriverManager.Tests.csproj

@@ -8,7 +8,7 @@
 
     <ItemGroup>
         <PackageReference Include="coverlet.msbuild" Version="2.7.0" />
-        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.3.0" />
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.4.0" />
         <PackageReference Include="Selenium.WebDriver" Version="3.141.0" />
         <PackageReference Include="xunit" Version="2.4.1" />
         <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" />