Setup changesets for v7 packages

[brophdawg11]

Replaces #11475 - was easier to make fresh changes instead of resolving conflicts in that branch

Validated by a dry run and then reverted the commits so you can still see what they produce for reference:

# Enter prerelease mode and commit changes
pnpm exec changeset pre enter pre
git add .
git commit -a -m "Enter prerelease mode"

# Run version command to bump to 7.0.0-pre.0 and add entries to CHANGELOG's
export GITHUB_TOKEN="....."
pnpm exec changeset version
git add .
git commit -m "Prerelease"

# Run a dry publish run to see what would be published to npm
pnpm -r publish --dry-run --publish-branch brophdawg11/changesets-2

[changeset-bot]

⚠️ No Changeset found

Latest commit: c813dd4

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 changesets to release 8 packages

Name	Type
react-router-dom	Major
@react-router/express	Major
react-router	Major
@react-router/serve	Major
@react-router/node	Major
@react-router/dev	Major
@react-router/architect	Major
@react-router/cloudflare	Major

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

[brophdawg11]

No longer exists 🙃

[brophdawg11]

Align these all to 6.x so they all bump to v7 together when we do the first alpha release

[brophdawg11]

Changesets requires everything in the monorepo to be versioned - even if it's not going to publish them

[github-actions]

🤖 Hello there,

We just published version 6.28.2-pre.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!