This cannot be used as a global plugin but only a local plugin

1. Install plugin

npx netlify-plugin-pnpm-preinstaller

2. Add it as the first plugin in your netlify toml file

[[plugins]]
     package = "./plugins/pnpm-preinstaller"

3. Prevent redundant npm install

[build.environment]
        NPM_FLAGS="--version"

4. Done!

This is not in active development, just something we made to use internally. If you find bugs or issue you can make an issue and we might get to it, no promises. Ideally just fork the repo and makes changes as needed