fix: allow Authorization header when doing CORS
fix: allow Authorization header when doing CORS

The Authorization header needs to be allowed when doing CORS because
otherwise /userinfo can't work.  It isn't one of the headers
explicitly allowed by default by Gorilla, so we have to call
handlers.AllowedHeaders() to specify it.

Issues: #1532
Signed-off-by: Alastair Houghton <11ae3d2e46cae696ddf200215f639ad6a8893312@alastairs-place.net>

ericchiang/dex,ericchiang/dex,coreos/dex,coreos/dex,coreos/dex,ericchiang/dex