v5.0.40

Upgrade to support PuppeteerSharp v19.

As PuppeteerSharp has switched from NewtonSoft.Json to System.Text.Json a few convenience methods have been removed.

• Element.GetAttributeAsync<T> has been removed, you can now only use GetAttributeAsync which returns a string (which matches the return type of the underlying getAttribute method).
• CssStyleDeclaration.GetPropertyValueAsync<T> has been removed, you can now only use GetPropertyValueAsync which returns a string (which matches the return type of the underlying getPropertyValue method).

Make sure to read the upstream release notes at https://github.com/hardkoded/puppeteer-sharp/releases/tag/v19.0.0