Add metadata to mark peer dependencies as optional for npm7+

[keeganstreet]

In npm 7 and npm 8, peer dependencies are installed by default.

iltorb and node-zopfli-es are only required for older versions of Node, and it doesn't make sense for them to be installed automatically when shrink-ray-current is installed.

This change adds a peerDependenciesMeta field to mark these peer dependencies as optional https://docs.npmjs.com/cli/v8/configuring-npm/package-json#peerdependenciesmeta

[keeganstreet]

Hi @Alorel , any chance you could release this patch?

The iltorb installation errors out in environments without python available. We don't need iltorb to be installed automatically (which is the default behaviour for peer dependencies in recent npm versions).

[ShrijalFetchly]

@keeganstreet @Alorel will this be merged?

[keeganstreet]

The maintainer is taking a bit of a break. The deprecated iltorb and node-zopfli-es packages can be blocked in consuming apps by adding the following config to the package.json file of the consuming app:

  "overrides": {
    "iltorb": "npm:node-noop",
    "node-zopfli-es": "npm:node-noop"
  }

This will install https://www.npmjs.com/package/node-noop (a placeholder package that doesn't do anything) instead of iltorb and node-zopfli-es.