Remove PostgreSQL 13 from supported versions in documentation.

Also add PostgreSQL 18 to supported versions.

Author: dwsteele

README.md

@@ -48,14 +48,16 @@ To limit the number of relations audit logged for `SELECT` and `DML` statements,
 
 ## PostgreSQL Version Compatibility
 
-pgAudit supports PostgreSQL 13 or greater.
+pgAudit supports PostgreSQL 14 or greater.
 
-In order to support new functionality introduced in each PostgreSQL release, pgAudit maintains a separate branch for each PostgreSQL major version (currently PostgreSQL 13 - 17) which will be maintained in a manner similar to the PostgreSQL project.
+In order to support new functionality introduced in each PostgreSQL release, pgAudit maintains a separate branch for each PostgreSQL major version (currently PostgreSQL 14 - 18) which will be maintained in a manner similar to the PostgreSQL project.
 
 Aside from bug fixes, no further development is allowed for stable branches. New development, if any, will be strictly for the next unreleased major version of PostgreSQL.
 
 pgAudit versions relate to PostgreSQL major versions as follows:
 
+- **pgAudit v18.X** is intended to support PostgreSQL 18.
+
 - **pgAudit v17.X** is intended to support PostgreSQL 17.
 
 - **pgAudit v16.X** is intended to support PostgreSQL 16.
@@ -64,8 +66,6 @@ pgAudit versions relate to PostgreSQL major versions as follows:
 
 - **pgAudit v1.6.X** is intended to support PostgreSQL 14.
 
-- **pgAudit v1.5.X** is intended to support PostgreSQL 13.
-
 ## Compile and Install
 
 pgAudit can be compiled against an installed copy of PostgreSQL with development packages using `PGXS`. The following instructions should work on most Unix-like operating systems.