Get rid of deprecated set-output commands in GitHub Actions

[roryabraham]

Problem

GitHub deprecated the set-output command in workflows, and they will "soon be disabled".

https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/
https://github.com/Expensify/App/actions/runs/3252739822/jobs/5339300870

Why is this important?

These were deprecated for security reasons, and if we don't update our workflows then they will stop working soon.

Solution

Update to using the new environment files.

[roryabraham]

Got a PR up for most of our usages of set-output, but not necessarily all the usages in the community actions we're using.

[melvin-bot]

@roryabraham Uh oh! This issue is overdue by 2 days. Don't forget to update your issues!

[roryabraham]

Reopening to continue migrating community actions.