Update HtmlParser2 version

HtmlParser2's `normalizeWhitespace` option is not functionally equivalent to the previous behavior of the `ignoreWhitespace` option, so two tests must be updated. Basically, instead of completely removing instances of two-or-more whitespace characters, such instances are now replaced with a single space character.

This could be considered a "breaking" change by some, so this probably warrants an increment to Cheerio's minor version.

This should resolve issues #265 and #262.

Commit message:

> The latest version of HtmlParser2 has deprecated the `ignoreWhitespace`
> option in favor of a new option, `normalizeWhitespace`.
> 
> Allow for future patch releases of HtmlParser2 to automatically
> "upstream" into Cheerio.