Don't try to import html5lib unless we are actually doing an update
Don't try to import html5lib unless we are actually doing an update

frewsxcv/wpt-tools,kaixinjxq/wpt-tools,wpt-on-tv-tf/wpt-tools,frewsxcv/wpt-tools,frewsxcv/wpt-tools,vivliostyle/wpt-tools,vivliostyle/wpt-tools,wpt-on-tv-tf/wpt-tools,UprootStaging/wpt-tools,vivliostyle/wpt-tools,kaixinjxq/wpt-tools,UprootStaging/wpt-tools,UprootStaging/wpt-tools,kaixinjxq/wpt-tools,wpt-on-tv-tf/wpt-tools