fix(ci) upgrade pnpm/action-setup to the current latest

[ro0gr]

it currently fails with the

Running self-installer...
   WARN  GET https://registry.npmjs.org/pnpm error (ERR_INVALID_THIS). Will retry in 10 seconds. 2 retries left.
   WARN  GET https://registry.npmjs.org/pnpm error (ERR_INVALID_THIS). Will retry in 1 minute. 1 retries left.
   ERR_PNPM_META_FETCH_FAIL  GET https://registry.npmjs.org/pnpm: Value of "this" must be of type URLSearchParams
Error: Something went wrong, self-installer exits with code 1

https://github.com/san650/ember-cli-page-object/actions/runs/11084629777/job/30825358176?pr=642#step:4:13

[ro0gr]

The original issue seems to be fixed, but it now fails for the release, beta, and canary scenarios with

Object.hasOwn is not a function

https://github.com/san650/ember-cli-page-object/actions/runs/11096086617/job/30825526505?pr=643#step:6:62

I suspect it's not related to the ec-page-object, or at least I can't see an obvious "why", so let's go ahead and make the most of scenarios run and green.

[ro0gr]

oh.. seems we need to upgrade to the node@16 to support the Object.hasOwn(, let's do it as a follow up then