Deprecated dependencies for @argdown/image-export

[dhicks]

@argdown/image-export has puppeteer@1.1.1 as a dependency, possibly via core-js@2.6.12. Trying to install @argdown/image-export, I'm encountering puppeteer/puppeteer#2173. That issue is closed, apparently resolved by a more recent version of puppeteer (current version is 14.0.0). But @argdown/image-export requires the older version. For the same reason, the various workarounds for installing puppeteer suggested in the issue thread don't work for @argdown/image-export.