[discourse-saml] Generated metadata has lost <md:KeyDescriptor use="encryption">

Somewhere in the recent flurry of updates (https://github.com/discourse/discourse-saml/compare/975adc6...master) the metadata generation (/auth/saml/metadata) has changed and it’s no longer producing the <md:KeyDescriptor use="encryption"> attribute. I assume this is due to a change in the ruby-saml gem version.

It would be very useful to have this back. :wink:

(I would have reported this on the GitHub page but the Issue Tracker isn’t enabled.)

Ping @vinothkannans