Ignore test screenshots folder in .gitignore (#2804)

* Small touch on tests project

* Ignore test screenshots folder in .gitignore

* Refactor EvaluationTests.ShouldAcceptObjectHandleAsAnArgument

Change variable type to object as test suggest

* Refactor .gitignore for tests screenshots

* Revert test object type change

Author: CaCTuCaTu4ECKuu

.gitignore

@@ -290,7 +290,7 @@ Thumbs.db
 
 # ignore local cert
 /lib/PuppeteerSharp.TestServer/testCert.cer
-/lib/PuppeteerSharp.Tests/Screenshots/test.png
+/lib/PuppeteerSharp.Tests/Screenshots/
 
 demos/PuppeteerSharpPdfDemo/google.pdf
 demos/PuppeteerSharpPdfDemo/.local-chromium/