Feature request: run pnpm with old version node

[chengcyber]

What

This is a feature request to this action supports run pnpm@6 in node@10 environment.

Why

I use pnpm@6 in local dev, but my package wants to support node>=10, which break the rule of pnpm@6, engines.node >=12.

Detail

add a parameter (maybe named compiled_install),
If true, instead of install pnpm directly, run sth like curl -f https://get.pnpm.io/v6.js | node - add --global pnpm to setup a compiled pnpm binary as pnpm CLI

[KSXGitHub]

pnpm itself requires Node.js >= 12.17, as seen here:

Node.js v10 support is dropped. At least Node.js v12.17 is required for the package to work

So I think this issue is more suitable at pnpm/pnpm. But before that, consider workaround: Bundling pnpm@6 with node 12.17 into a self-contained binary.

[zkochan]

We can do this easily by installing @pnpm/exe instead of pnpm. However, @pnpm/exe is only available since v6.17.1. So this will be a breaking change. But I think it is OK to do this breaking change since it will make pnpm work with older Node.js versions.