Updated v5.5 release notes

Author: tillkruss

CHANGELOG-5.5.md

@@ -19,7 +19,7 @@
 - Renamed `$parent` property to `$pivotParent` in `Pivot` class ([#17933](https://github.com/laravel/framework/pull/17933), [#18150](https://github.com/laravel/framework/pull/18150))
 - ⚠️ Don't add `_count` suffix to column name when using `withCount()` with an alias ([#17871](https://github.com/laravel/framework/pull/17871))
 - ⚠️ Renamed `$events` to `$dispatchesEvents` ([#17961](https://github.com/laravel/framework/pull/17961), [b6472bf](https://github.com/laravel/framework/commit/b6472bf6fec1af6e76604aaf3f7fed665440ac66), [3dbe12f](https://github.com/laravel/framework/commit/3dbe12f16f470e3bca868576d517d57876bc50af))
-- ⚠️ Added `$parentKey` parameter to `belongsToMany()`, `BelongsToMany` and `MorphToMany` ([#17915](https://github.com/laravel/framework/pull/17915))
+- ⚠️ Added `$parentKey` parameter to `belongsToMany()`, `BelongsToMany` and `MorphToMany` ([#17915](https://github.com/laravel/framework/pull/17915), [#18380](https://github.com/laravel/framework/pull/18380))
 
 ### Events
 - ⚠️ Removed calling queue method on handlers ([0360cb1](https://github.com/laravel/framework/commit/0360cb1c6b71ec89d406517b19d1508511e98fb5), [ec96979](https://github.com/laravel/framework/commit/ec969797878f2c731034455af2397110732d14c4), [d9be4bf](https://github.com/laravel/framework/commit/d9be4bfe0367a8e07eed4931bdabf135292abb1b))
@@ -29,6 +29,11 @@
 - ⚠️ Ensure `Arrayable` objects are also morphed by `Response` ([#17868](https://github.com/laravel/framework/pull/17868))
 - Added `SameSite` support to `CookieJar` ([#18040](https://github.com/laravel/framework/pull/18040), [#18059](https://github.com/laravel/framework/pull/18059), [e69d722](https://github.com/laravel/framework/commit/e69d72296cfd9969db569b950721461a521100c4))
 - Accept `HeaderBag` in `ResponseTrait::withHeaders()` ([#18161](https://github.com/laravel/framework/pull/18161))
+- ⚠️ Reset response content-type in `Response::setContent()` ([#18314](https://github.com/laravel/framework/pull/18314))
+
+### Mail
+- Allow mailables to be rendered directly to views ([d9a6dfa](https://github.com/laravel/framework/commit/d9a6dfa4f46a10feceb67921b78c60a905b7c28c))
+- Allow for per-mailable theme configuration ([b2c35ca](https://github.com/laravel/framework/commit/b2c35ca9eb769d1a4752a64e936defd7f7099043))
 
 ### Queue
 - ⚠️ Removed redundant `$queue` parameter from `Queue::createPayload()` ([#17948](https://github.com/laravel/framework/pull/17948))
@@ -45,6 +50,7 @@
 ### Testing
 - ⚠️ Switched to PHPUnit 6 ([#17755](https://github.com/laravel/framework/pull/17755), [#17864](https://github.com/laravel/framework/pull/17864))
 - ⚠️ Renamed authentication assertion methods ([#17924](https://github.com/laravel/framework/pull/17924), [494a177](https://github.com/laravel/framework/commit/494a1774f217f0cd6b4efade63e200e3ac65f201))
+- Added POC of integration testing the framework itself ([182027d](https://github.com/laravel/framework/commit/182027d3290e9a2e1bd9e2d52c125177ef6c6af6))
 
 ### Views
 - ⚠️ Camel case variables names passed to views ([#18083](https://github.com/laravel/framework/pull/18083))