Introduce `--update-docs` flag to synchronously update Theme Check resources (objects, filters, and tags)

Fixes part of https://github.com/Shopify/theme-check/issues/706 (a following PR is going to update Shopify/theme-check-action)

Summary

This PR introduces a flag to synchronously update Theme Check documentation (objects, filters, and tags).

Context

When Theme Check is released, the most updated version of Shopify/theme-liquid-docs is embedded. Also, when some new filter is released, local Theme Check instances get auto upgraded asynchronously (so documentation is always updated on developers machines).

However, at CI environments, Theme Check uses the embedded documentation from the latest release, which makes the build of some CI-users fail.

How to test this PR

Download this filters.json file
Replace your local filters.json file (data/shopify_liquid/documentation/filters.json) with the one above
Run shopify-dev theme init
Remove the comments from the sections/footer.liquid file (line ~192, around the login_button filter)
Run bin/theme-check <theme_directory> | grep sections/footer.liquid
Notice that Theme Check raises an error
Run bin/theme-check <theme_directory> --update-docs | grep sections/footer.liquid
Notice that errors are no longer raised

Post-release steps

Update Theme Check docs
Update Theme Check action

Shopify / theme-check