fix(travis): fetch GPG key with url
fix(travis): fetch GPG key with url

The issue is that the pgp.mit.edu keyserver sometimes has outages,
which results in the error message you're seeing. Loading the
GPG key via URL should be more reliable.

angular/flex-layout,benbraou/flex-layout,atscott/flex-layout,angular/flex-layout,karlhaas/flex-layout,brendanoffer/flex-layout,atscott/flex-layout,DevVersion/flex-layout,atscott/flex-layout,DevVersion/flex-layout,brendanoffer/flex-layout,angular/flex-layout,benbraou/flex-layout,benbraou/flex-layout,atscott/flex-layout,karlhaas/flex-layout,DevVersion/flex-layout,angular/flex-layout,brendanoffer/flex-layout,benbraou/flex-layout,d3viant0ne/flex-layout,d3viant0ne/flex-layout,karlhaas/flex-layout,d3viant0ne/flex-layout