action-setup should print the version of pnpm that it picked

v5 produced output like

Run pnpm/action-setup@v5
  with:
    dest: ~/setup-pnpm
    run_install: null
    cache: false
    cache_dependency_path: pnpm-lock.yaml
    package_json_file: package.json
    standalone: false
  env:
    APP_ID: 1013567
    CLIENT_ID: Iv23liXTAsX4IYm9H6lc
    DATABASE_URL: file:./test.db
Running self-installer...
  (node:2245) [DEP0169] DeprecationWarning: `url.parse()` behavior is not standardized and prone to errors that have security implications. Use the WHATWG URL API instead. CVEs are not issued for `url.parse()` vulnerabilities.
  (Use `node --trace-deprecation ...` to show where the warning was created)
  Progress: resolved 1, reused 0, downloaded 0, added 0
  Packages: +1
  +
  Progress: resolved 1, reused 0, downloaded 1, added 1, done
  
  dependencies:
  + pnpm 10.30.2 (10.33.2 is available)
  
  Done in 764ms
Installation Completed!

v6 produces output like

Run pnpm/action-setup@v6
  with:
    dest: ~/setup-pnpm
    run_install: null
    cache: false
    cache_dependency_path: pnpm-lock.yaml
    package_json_file: package.json
    standalone: false
  env:
    APP_ID: 1013567
    CLIENT_ID: Iv23liXTAsX4IYm9H6lc
    DATABASE_URL: file:./test.db
Running self-installer...
  
  added 5 packages, and audited 6 packages in 2s
  
  2 packages are looking for funding
    run `npm fund` for details
  
  found 0 vulnerabilities
Installation Completed!

This obscures the fact that v6 is ignoring the version specified in the packageManager field of package.json, as reported in #225.

Start with the action-setup entry point and the packageManager field in package.json, then trace how v6 selects and installs pnpm. Compare the installer output with the v5 example and verify that the selected pnpm version is printed and that the packageManager-specified version is not silently ignored.