bump ffi to fix TypeError: Unable to resolve type 'size_t'
bump ffi to fix TypeError: Unable to resolve type 'size_t'

flag = none

Test plan:
• run `bundle install`
• run `bundle exec rails canvas:compile_assets
• verify no errors related to commit message

Change-Id: I0e9a4adfbff519970ec64e3436e10d4a41081985
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/284079
Reviewed-by: Jacob Burroughs <8ecea6e385af5cf9f53123f5ca17fb5fd6a6d4b2@instructure.com>
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
QA-Review: August Thornton <9adc7a1161ddf32ff608de792a7e50179545f026@instructure.com>
Product-Review: August Thornton <9adc7a1161ddf32ff608de792a7e50179545f026@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms