Correct the PROJECT_PIPELINES_LIMIT variable on-prem documentation with correct service

Author: vadim-kharin-codefresh

codefresh/README.md

@@ -1143,7 +1143,7 @@ cfapi:
 ### Projects pipelines limit
 
 ```yaml
-cfapi:
+pipeline-manager:
   env:
     # Determines project's pipelines limit (default: 500)
     PROJECT_PIPELINES_LIMIT: 500