Mark the http-equiv value set-cookie as deprecated (#4341)
Mark the http-equiv value set-cookie as deprecated (#4341)

This is not supported anymore in Firefox 68

Source:
* https://bugzilla.mozilla.org/show_bug.cgi?id=1457503
* https://github.com/whatwg/html/pull/3649
chrisdavidmills/browser-compat-data,chrisdavidmills/browser-compat-data,mdn/browser-compat-data,mdn/browser-compat-data