Support pnpm cache

[allbetter-max]

Hi guys,

In order to use volta on CI instead of actions/setup-node a piece of missing functionality needs to be filled in.

Please see https://github.com/actions/setup-node#caching-global-packages-data, we're using pnpm as the package manager and the node action solves the problem of caching this whole pile of libs.

Side Note,

It seems that volta will soon supprt pnpm, which brings this yet another step towards a logical next step https://github.com/volta-cli/volta/issues/737#issuecomment-1309700437