Merge branch 'prep-release-3.1.0' into develop-ascraeus
* prep-release-3.1.0:
[ticket/13227] Properly handle curlwrapper headers in remote avatars
[ticket/13231] Update the dependencies of the migration contact_admin_form
[ticket/13227] Properly handle curlwrapper headers in remote avatars
Read a bit of the file to ensure header values are populated and then
handle headers in the nested array structure too.