This is an update of dependencies, specifically it updates the HTML parser within go/net/html.
The update removes a capability, Microsoft style comments that allow browser conditionals no longer works. This is due to a fix on the part of the Go team to prevent XSS within HTML comments, and the commit in question is here golang/net@06994584 . There is no easy to see safe way to restore that functionality without adding more risk to those who .AllowComments() and so I am accepting that this non-standard use of HTML comments is no longer supported.
As part of this version, the older release of v1.0.19 is retracted.