Update CHANGELOG for version 18.0 release

- Follow PostgreSQL version numbering (6.0 → 18.0)
- Document comprehensive PostgreSQL 13-17 support
- Record CircleCI to GitHub Actions migration
- Note PostgreSQL 17 compatibility improvements
- Mark as breaking change due to version jump

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: NikolayS

CHANGELOG.md

@@ -3,24 +3,37 @@
 All notable changes to postgres_dba will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
-and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+and this project follows PostgreSQL version numbering.
 
-## [Unreleased]
+## [18.0] - 2025-01-28
 
 ### Added
-- GitHub Actions workflow for testing PostgreSQL versions 13-17
+- GitHub Actions workflow for comprehensive testing across PostgreSQL versions 13-17
+- PostgreSQL 17 compatibility with new `pg_stat_checkpointer` view
 - Multi-version PostgreSQL testing support in CI/CD pipeline
+- Dynamic PL/pgSQL functions for version-aware checkpoint statistics
+- Flexible regression testing for cross-version compatibility
+- Support for all currently supported PostgreSQL versions (13-17)
 
 ### Changed
+- **BREAKING**: Now follows PostgreSQL version numbering (jumping from 6.0 to 18.0)
 - Migrated CI/CD from CircleCI to GitHub Actions
 - Simplified PostgreSQL client installation process for better version compatibility
 - Updated test configuration to support multiple PostgreSQL versions
+- Improved regression tests to handle storage variations between PostgreSQL versions
 
 ### Fixed
+- PostgreSQL 17 compatibility issues with `pg_stat_bgwriter` → `pg_stat_checkpointer` migration
+- Column mapping for PostgreSQL 17: `checkpoints_timed` → `num_timed`, `checkpoints_req` → `num_requested`, `buffers_checkpoint` → `buffers_written`
 - PostgreSQL client installation issues across different versions
 - GitHub Actions PostgreSQL configuration for proper test execution
+- Query planning errors when using version-specific system views
 
-## [0.1.0] - Initial Release
+### Removed
+- CircleCI configuration and all related references
+- PostgreSQL beta version testing (18-beta, 19-beta) due to Docker image availability
+
+## [6.0] - 2020
 
 ### Added
 - Core database administration functionality