Add supported PostgreSQL versions section to README

- Document support for PostgreSQL 13-18
- Highlight PostgreSQL 17 pg_stat_checkpointer compatibility
- Mention PostgreSQL 18 as latest supported version
- Note that older versions may work but aren't actively tested
- Provides clear version compatibility information for users

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

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

Author: NikolayS

README.md

@@ -34,6 +34,19 @@ sudo apt-get install -y postgresql-client-12
 
 Using alternative psql pager called "pspg" is highly recommended (but not required): https://github.com/okbob/pspg.
 
+## Supported PostgreSQL Versions
+
+**postgres_dba** is tested and supports **PostgreSQL 13-18**, including the latest PostgreSQL 18 release.
+
+- ✅ **PostgreSQL 13** - Fully supported
+- ✅ **PostgreSQL 14** - Fully supported  
+- ✅ **PostgreSQL 15** - Fully supported
+- ✅ **PostgreSQL 16** - Fully supported
+- ✅ **PostgreSQL 17** - Fully supported (includes pg_stat_checkpointer compatibility)
+- ✅ **PostgreSQL 18** - Fully supported (latest release)
+
+Older versions (9.6-12) may work but are not actively tested. Some reports may require specific PostgreSQL features introduced in newer versions.
+
 ## Installation
 The installation is trivial. Clone the repository and put "dba" alias to your `.psqlrc` file (works in bash, zsh, and csh):
 ```bash