Dockerfile: add utility required for building fonts
Dockerfile: add utility required for building fonts

Building of fonts fails unless we have sfnt2woff

Test Plan:

  - Make sure image is built successfully
  - Make sure the following command succeeds:
    - docker-compose run --rm web bundle exec fontcustom compile --force

Change-Id: Ie7fa7e701584894ee5fd6d1eea7d4144c512b5bf
Reviewed-on: https://gerrit.instructure.com/69103
Tested-by: Jenkins
Reviewed-by: Brian Palmer <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@instructure.com>
QA-Review: Michael Hargiss <59e3fde81b8d9a4f5e0cc016a3c2695591912604@instructure.com>
Product-Review: Benjamin Porter <fdd60f2e3d506934848b3d0fff79c55f544a2d47@instructure.com>

instructure/canvas-lms,sfu/canvas-lms,redconfetti/canvas-lms,djbender/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,dgynn/canvas-lms,djbender/canvas-lms,SwinburneOnline/canvas-lms,roxolan/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,fronteerio/canvas-lms,HotChalk/canvas-lms,sfu/canvas-lms,HotChalk/canvas-lms,instructure/canvas-lms,SwinburneOnline/canvas-lms,grahamb/canvas-lms,grahamb/canvas-lms,instructure/canvas-lms,roxolan/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,roxolan/canvas-lms,sfu/canvas-lms,fronteerio/canvas-lms,grahamb/canvas-lms,matematikk-mooc/canvas-lms,roxolan/canvas-lms,redconfetti/canvas-lms,fronteerio/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,dgynn/canvas-lms,dgynn/canvas-lms,djbender/canvas-lms,venturehive/canvas-lms,SwinburneOnline/canvas-lms,instructure/canvas-lms,grahamb/canvas-lms,fronteerio/canvas-lms,HotChalk/canvas-lms,redconfetti/canvas-lms,matematikk-mooc/canvas-lms,matematikk-mooc/canvas-lms,redconfetti/canvas-lms,instructure/canvas-lms,dgynn/canvas-lms,venturehive/canvas-lms,matematikk-mooc/canvas-lms,HotChalk/canvas-lms