Fix to work Chrome's BGPT feature in preview window

[yhatt]

Puppeteer v1.13.0 (Updated in #76) has disabled BGPT feature due to Chrome's bug in capturing screen shot. We following this decision when converting to PDF and image.

But it would revert element's incorrect positioning when opened preview window by --preview option. This problem can show by using <video> element in Markdown with --html option.

echo '<video src="http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4" autoplay muted controls />' | npx @marp-team/marp-cli --html -p --no-output

We have to override --disable-features option to prevent disabling BGPT. It will get back an expected scaling.

Requires Chrome Canary. A stable Chrome still has incorrect rendering.