update link for API terms of service
update link for API terms of service

Closes: DOC-1008

test plan:
- make sure API terms of service link works

Change-Id: I29a946a6e5dabe2ea886e99a1db69b88fd55cfca
Reviewed-on: https://gerrit.instructure.com/181826
Tested-by: Jenkins
Reviewed-by: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
QA-Review: Erin Hallmark <2a4b17b11682b229726079a631360cf016a43450@instructure.com>
Product-Review: Erin Hallmark <2a4b17b11682b229726079a631360cf016a43450@instructure.com>

instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms