Also updating and adding whatever the new version of npm wants to be
updated and added in its package files. This should not affect the
behavior of the action.
GitHub Actions tutorials suggest that you should not commit Node.js crap
onto your master branch, but it's not like this action has a lot of
dependencies, and not being able to test "ilammy/msvc-dev-cmd@master" is
so annoying... Therefore, do
npm install --only production
and commit the results.