The hash keys were missing hash for package.json and yarn.lock
because they were not present since we don't do a full checkout
in this job. We fix this by sending over those files and generating
hashes from them.
I usally verify these cache keys by clicking the Restore <cache>
step dropdown menu and then clicking the Run ... dropdown menu again
to see the generated hash.
This directory contains scripts that are used in building, managing,
testing, and other forms of work in a Zulip development environment.
Note that tools that are also useful in production belong in
scripts/ or should be Django management commands.