Add minimum code coverage standards
Add minimum code coverage standards

This ensures we don't fall back on code coverage.
We should increase these numbers as we increase coverage

Test Plan:
  - Automated tests pass

Change-Id: I7174bb87e01ac0a0cae34edd7c0924c423816df2
Reviewed-on: https://gerrit.instructure.com/109893
Tested-by: Jenkins
Reviewed-by: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>
Product-Review: Clay Diffrient <9dff2e5c98626d20d2848250c411e8009465bb87@instructure.com>
QA-Review: Clay Diffrient <9dff2e5c98626d20d2848250c411e8009465bb87@instructure.com>

instructure/canvas-planner,instructure/canvas-planner,instructure/canvas-planner