Update yarn.lock
Update yarn.lock

whenever canvas-lms is updated, we get a new yarn.lock with a
subtly different node-sass entry. Let's finally check it in

closes: LA-243

test plan: n/a

Change-Id: I76de33c59aef5380d85df290132be86fac8b2660
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/218133
Tested-by: Jenkins
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>
QA-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>
Product-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>

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