pnpm Support

[misogihagi]

Description:
I'm using pnpm in my project.
setup-node does not work.

Run actions/setup-node@v4
Node version file is not JSON file
Resolved .node-version as 21.6.2
Attempting to download 21.6.2...
Not found in manifest. Falling back to download directly from Node
Acquiring 21.6.2 - x64 from https://nodejs.org/dist/v21.6.2/node-v21.6.2-linux-x64.tar.gz
Extracting ...
/usr/bin/tar xz --strip 1 --warning=no-unknown-keyword --overwrite -C /home/runner/work/_temp/c6e9e174-8852-4a50-b423-4526257ae884 -f /home/runner/work/_temp/e3b0661a-cfe3-408e-b1c4-7e2616add902
Adding to the cache ...
Done
Environment details
/opt/hostedtoolcache/node/21.6.2/x64/bin/npm config get cache
/home/runner/.npm
Error: Dependencies lock file is not found in /home/runner/work/lighthouse-ci-datadog-action/lighthouse-ci-datadog-action. Supported file patterns: package-lock.json,npm-shrinkwrap.json,yarn.lock

Justification:
yarn is available. why don't we use also pnpm?

[priyagupta108]

Hi, @misogihagi 👋, Thank you for the feature request, we will investigate it and get back to you as soon as we have updates.