chore: update CHANGELOG.md to remove version labels and improve formatting

Author: orestesgaolin

codemagic_manager/CHANGELOG.md

@@ -1,53 +1,75 @@
-## [0.4.0] - Dart SDK 3.0.0 and null safety
+## 0.4.0
 
 - Updated dependencies
 - Migrated to null safety
 
-## [0.3.0+1] - Maintenance update
+## 0.3.0+1
+
+Maintenance update
 
 - Docs update
 
-## [0.3.0] - Null-safety support
+## 0.3.0
+
+Null-safety support
 
 - Migrate to null-safety - please report bugs if found!
 
-## [0.3.0-nullsafety.1] - Null-safety migration
+## 0.3.0-nullsafety.1
+
+Null-safety migration
 
 - update docs
 
-## [0.3.0-nullsafety.0] - Null-safety migration
+## 0.3.0-nullsafety.0
+
+Null-safety migration
 
 - Migrated to nnbd
 - Removed freezed dependency
 - Removed dio dependency in favor of HttpClient
 - Added basic tests
 - Simplified API - some properties might change, so please this might be slight BREAKING CHANGE
 
-## [0.2.1] - Tweaks and docs
+## 0.2.1
+
+Tweaks and docs
 
 - Updated docs and dependencies
 - Removed `sshAccessEnabled` in `startBuild` as it's [no longer configured when starting build](https://docs.codemagic.io/troubleshooting/accessing-builder-machine-via-ssh/) but always available
 
-## [0.2.0] - Starting and cancelling builds
+## 0.2.0
+
+Starting and cancelling builds
 
 - Added methods to start and cancel running build
 
-## [0.1.3] - Platform issues
+## 0.1.3
+
+Platform issues
 
 - Fixed missing platforms
 
-## [0.1.2+1] - Package info
+## 0.1.2+1
+
+Package info
 
 - Added some package information like issue tracker
 
-## [0.1.2] - Platforms
+## 0.1.2
+
+Platforms
 
 - Added missing platforms
 
-## [0.1.1+1] - Improvements
+## 0.1.1+1
+
+Improvements
 
 - Improve quality of code, document API etc.
 
-## [0.1.0] - Initial release 🎉
+## 0.1.0
+
+Initial release 🎉
 
 - First version allowing to query applications and builds in a limited manner