fix: Replace TOC link with the correct item Third-party extensions (#523)

Author: dimio

README.md

@@ -29,7 +29,7 @@ See also [why not Quartz?](#why-db-scheduler-when-there-is-quartz)
 * [Who uses db-scheduler?](#who-uses-db-scheduler)
 * [Examples](#examples)
 * [Configuration](#configuration)
-* [Third-party task repositories](#third-party-task-repositories)
+* [Third-party extensions](#third-party-extensions)
 * [Spring Boot usage](#spring-boot-usage)
 * [Interacting with scheduled executions using the SchedulerClient](#interacting-with-scheduled-executions-using-the-schedulerclient)
 * [How it works](#how-it-works)