align rspec version in gems with parent

update spec_helpers to fix deprecation warning after upgrade

Change-Id: I31b370d1d60f73d5256c69a8d5e69418657f880d
Reviewed-on: https://gerrit.instructure.com/39144
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Brian Palmer <brianp@instructure.com>
Product-Review: Paul Hinze <paulh@instructure.com>
QA-Review: Paul Hinze <paulh@instructure.com>