Prebuild error when using pnpm

[CryogenicPlanet]

Describe the bug
I am using pnpm on a nextjs repository and followed the steps here https://answers.netlify.com/t/using-pnpm-and-pnpm-workspaces/2759 and netlify/build#1633 (comment) this was working fine with next-on-netlify

However now with this plugin, I run into an error that says next is not installed on the prebuild by the plugin, which runs before my custom prebuild which installs the packages.

Also, this might be better categorized as a feature request, not entirely sure which it falls under exactly

To Reproduce

Steps to reproduce the behaviour:

1. Create a next project with pnpm and the below netlify.toml
2. Push to netlify and build without cache. (I think it worked the first few times for me because it has next cached from yarn before, we just migrated over)
3. Should see the error in the console

This repo can be used to reproduce the bug https://github.com/CryogenicPlanet/netlify-next-prebuild-bug

Expected behaviour
A workaround or suggestion to use pnpm with this new plugin would be great or a way to disable the plugins prebuild

Versions

• Next.js: latest
• plugin (if installed at fixed version): 3.1.0

If you're using file-based installation

// netlify.toml
[build]
  command   = "npm run build"
  publish   = "out"
[build.environment]
  NPM_FLAGS="--prefix=/dev/null"  
[[plugins]]
  package = "@netlify/plugin-nextjs"

[mcmxcdev]

Encountering the same issue. Please prioritize this higher as it is a major blocker when using pnpm with next.

[ascorbic]

With the new plugin version you can use the workaround, though with one change: instead of --prefix=/dev/null, pass --version as the flag. Of course native pnpm support would be best, but this is the best solution for now