chore: add changelog for version 3.0.0 with breaking changes

Author: villelahdenvuo

.markdown-lint.yml

@@ -26,3 +26,6 @@ MD046:
 # Allow hard tabs in code
 MD010:
   ignore_code_blocks: true
+
+# Disable duplicate headings (for CHANGELOG.md)
+MD024: false

CHANGELOG.md

@@ -0,0 +1,23 @@
+<!-- markdownlint-disable MD024 -->
+
+# Changelog
+
+## [3.0.0] - 2025-12-17
+
+### Breaking Changes
+
+- Changed `max-annotations` to apply per annotation type (error/warning/notice)
+  instead of globally. Default reduced from 50 to 10.
+- Added new `token` input for GitHub API access (required for PR comments).
+- Support for creating PR comments when annotations are skipped due to limits.
+
+## [2.0.0]
+
+- Prioritize error annotations over warnings and notices when limits are
+  reached.
+
+## [1.0.0]
+
+### Added
+
+- Initial release of the report annotation action.