Configure publishing workflow

[lopert]

Sets up the release workflow as per our docs.

This is the first step of the following flow:

  1. Merge this PR (with workflow + changesets setup) to main
    - Workflow runs but does nothing (no changesets = no action)
  2. Create a new PR with a changeset and merge to main
    - Workflow runs and creates/updates a "Version Packages" PR
    - This PR will show the version bump and changelog updates
  3. Merge the "Version Packages" PR to main
    - Workflow runs and publishes to npm.js
    - Creates git tags

[saga-dasgupta]

Lines up with the instructions on the vault page.

[saga-dasgupta]

In the README I have all commands as pnpm build, pnpm test etc, should we keep it that way here as well?

[lopert]

I think either way is fine. In our CI.yml workflow, it uses the run variants, so I'll keep this one here with it as well for consistency.

[saga-dasgupta]

Should we also make this env variable up top for better visibility?

[lopert]

Good call. I think it's worth having split out since we will want to easily find it when it comes to updating things to stay consistent with what the CLI expects.