feat(ci): faster runs

[gabrielmfern]

This PR makes the following changes for CI to be faster:

• Use pnpm's action setup instead of manually doing it with corepack (saves a few seconds)
• Merges the build and test workflows to avoid downloading/uploading cache multiple times (saves a few minutes)
• Ensures that the caches between turbo test and turbo build are properly re-used (saves a few minutes when running hot)
  • main issue was that the environment variables for turbo build and turbo test were different, causing a cache miss
• Ensures that the demo and web properly depend on pnpm-lock so that they are cached on second build (saves a bit more than a minute when hot)

Running once cold, and then hot I got:

• 5m 13s when running cold
• 54s when running hot

[changeset-bot]

⚠️ No Changeset found

Latest commit: 5244c44

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
react-email	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Apr 24, 2025 2:09pm
react-email-demo	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Apr 24, 2025 2:09pm