Error `expected function, found 'object'` error when running postgraphile in cli mode

[RuiLoureiro]

Describe the bug
When running postgraphile in cli mode, with --append-plugins postgraphile-remove-foreign-key-fields-plugin, I get the error
Error: No plugin found matching spec 'postgraphile-remove-foreign-key-fields-plugin' - expected function, found 'object'.

If I purposefully misspell the package name, the error is different, so I believe it is finding the plugin.

To Reproduce
Steps to reproduce the behavior:

1. run npm install postgraphile-remove-foreign-key-fields-plugin`
2. run npx postgraphile --append-plugins postgraphile-remove-foreign-key-fields-plugin

Expected behavior
Postgraphile should run normally

Additional context

• postgraphile version 4.12.9
• plugin version 1.2.0