Update Stack component to use CSS gap

[felixhabib]

• Update Stack component to use CSS gap, simplifying the component
• Remove unused Divider component
• Callout browser policy in README

[changeset-bot]

🦋 Changeset detected

Latest commit: e5aecb0

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
playroom	Minor

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[askoufis]

I think this should have a changeset. It's something that benefits the UI, so should be released. Don't know how to word it though, as it's not really worth detailing implementation changes. 🤔

[askoufis]

Branch is not up to date, but you can still merge for some reason.

I think that should be disabled in the repo settings though 🤔

[askoufis]

I wouldn't really call out this as a perf change. Maybe it is just worth saying something like Use CSS gap for spacing or something.

I do think it's worth adding a note to the README saying that Playroom will only ever utilize features supported by all browers, but it assumes you have the latest stable version of any of the major browsers.