meta: Update changelog for v6.3.0

[iker-barriocanal]

No description provided.

[lobsterkatie]

It's nice if we can group them by category, similar to how it's done here: https://github.com/getsentry/sentry-javascript/blob/master/CHANGELOG.md#624.

[kamilogorek]

Can we sort it by package name + type? It's kinda hard to read now.

[packageA] feat:
[packageA] fix:
[packageA] ref:
[packageB] feat:
[packageB] fix:
[packageB] ref:

[lobsterkatie]

I'd nominate all of the below for removal. If someone truly wants to see everything that happened, they can look at the list of commits. IMHO the purpose of a changelog is to succinctly describe the things that actually have a likelihood of either being interesting to people, affecting their use of the SDK, or explaining why some behavior has changed.

[github-actions]

size-limit report

Path	Size
@sentry/browser - CDN Bundle (gzipped)	20.6 KB (-0.01% 🔽)
@sentry/browser - Webpack	21.48 KB (0%)
@sentry/react - Webpack	21.52 KB (0%)
@sentry/browser + @sentry/tracing - CDN Bundle (gzipped)	27.82 KB (-0.01% 🔽)