Update nightly release to use pnpm since it checks out the dev branch

[brophdawg11]

It looks like your nightly releases broke with the pnpm switch. Since the nightly workflow runs on a cron job, it always uses the workflow file from main, even though it checks out the source code from dev - per this comment I found when I went to check out the workflow 🤣

# HEADS UP! this "nightly" job will only ever run on the `main` branch due to it being a cron job,
# and the last commit on main will be what github shows as the trigger
# however in the checkout below we specify the `dev` branch, so all the scripts
# in this job will be ran from that, confusing i know, so in some cases we'll need to create
# multiple PRs when modifying nightly release processes

This copies the updated file from dev down to main and hopefully tonights nightly release will pass 🤞

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