golang: ignore CVE-2021-33194

This is a bug in golang.org/x/net/html/parse.go. The golang compiler
includes a partial copy of this under src/vendor/golang.org/x/net/
however the "html" subdirectory is not included. So this bug does not
apply to the compiler itself.

Signed-off-by: Ralph Siemsen <ralph.siemsen@linaro.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>