Shouldn't pify be a normal `dependency`?

[cecilia-sanare]

Description

Recently I've been running into the following error when using the remove-lockfiles module.

Error: Cannot find module 'pify'
Require stack:
- /Users/nick/Repositories/public/salte-auth/auth0/node_modules/force-del/lib/regular-remove.js
- /Users/nick/Repositories/public/salte-auth/auth0/node_modules/force-del/lib/delete-file.js
- /Users/nick/Repositories/public/salte-auth/auth0/node_modules/force-del/index.js
- /Users/nick/Repositories/public/salte-auth/auth0/node_modules/remove-lockfiles/index.js
- /Users/nick/Repositories/public/salte-auth/auth0/node_modules/remove-lockfiles/cli.js

My best guess as to why this is suddenly occurring is that some other library had pify listed as a dependency.

Shouldn't pify be listed as a dependency rather than a devDependency of this module?