[feature request] add pnpm supported

[lookis]

pnpm's market is increasing, some opensource project such as vuejs is fully moving to pnpm. It's better to add pnpm supported.

[daiwanxing]

Until now, pnpm is still not supported🫤

[cldfzn]

Is there interest on the Paketo side for these changes? What scope would be acceptable?

[zur4ik]

When pnpm support will be added?