Add changelog for 8.x (alpha) release

[adinauer]

#skip-changelog

📜 Description

💡 Motivation and Context

💚 How did you test it?

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

[github-actions]

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against 7354d05

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	382.82 ms	453.98 ms	71.16 ms
Size	1.70 MiB	2.28 MiB	596.35 KiB

Baseline results on branch: 8.x.x

Startup times

Revision	Plain	With Sentry	Diff
3e1e45b	373.72 ms	439.33 ms	65.60 ms
9f2c855	424.20 ms	506.34 ms	82.14 ms

App size

Revision	Plain	With Sentry	Diff
3e1e45b	1.70 MiB	2.28 MiB	596.32 KiB
9f2c855	1.70 MiB	2.28 MiB	596.32 KiB

Previous results on branch: feat/8.x-changelog

Startup times

Revision	Plain	With Sentry	Diff
2b15069	410.63 ms	492.43 ms	81.79 ms

App size

Revision	Plain	With Sentry	Diff
2b15069	1.70 MiB	2.28 MiB	596.33 KiB

[markushi]

LGTM!