[dagit] Eliminate caniuse-lite is outdated warning
Just reducing noise. Seen while running dev webapp.
Not sure how permanent this solution really is, so I'll keep an eye on it.
Test Plan: Run yarn, then run dagit, verify that the warning is gone.
Reviewers: bengotow, sashank, prha
Reviewed By: sashank
Differential Revision: https://dagster.phacility.com/D4569