allow activesupport 5.0
allow activesupport 5.0

Change-Id: I177b3554bbf0ecc01b3425826deb9247c347e984
Reviewed-on: https://gerrit.instructure.com/76780
Tested-by: Jenkins
Reviewed-by: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>
Product-Review: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
QA-Review: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>

instructure/ruby-saml2,instructure/ruby-saml2