fix typo in changelog

Author: biggerfisch

changelog.d/22094_postgresql_metrics_source_pg_17.enhancement.md

@@ -1,6 +1,6 @@
 Updates the `postgresql_metrics` source to support PostgreSQL 17.
 
-When upgrading to PostgreSQL 17, some metric will effectively be renamed due to having been moved to
+When upgrading to PostgreSQL 17, some metrics will effectively be renamed due to having been moved to
 another view. However, these metrics have, until now, not been collected on PostgreSQL 17+
 versions, so there is no actual breakage.