Svix

* Libs/JS: Fix for setting Idempotency-Key when one isn't set 🐞
* Libs/All: Add `msg_id` to attempt list responses (`MessageAttemptOut`)
* Libs/All: New GetOrCreate application function 🆕
* Server: Remove deprecated axum API usage
* Server: Implement PATCH for endpoint headers API 🆕
* Server: Add support for an endpoint cache for improved performance when sending 🚀

* Libs: Support for passing an idempotency key to post commands
* Libs: Add support for filtering by channel
* Kotlin & Go: Support filtering by event type
* JS: fix for API calls using a default idempotency key when one isn't set 🐞

* Server: Set custom endpoint headers when sending via worker
* Libs: Add support for filtering by StatusCodeClass in attempts API

* Libs: Add support for reverse iteration (prev_iterator) & after param in list commands ⬅️
* Server: Add support for adding & managing custom Endpoint Headers 🆕

* Libs: Support for new `/attempt/` API via list_for_msg and list_for_endpoint. 🚀
* **Deprecation warning:** `message_attempt.list` is deprecated in favor of this new API. ❌

* CI: Autorelease server artifacts on github releases 🆕