Update docker-compose.yml (#351)

Fix wrong data type in comment section from  string to integer

Author: piky

src/postgres/.devcontainer/docker-compose.yml

@@ -28,7 +28,7 @@ services:
       POSTGRES_DB: postgres
       POSTGRES_PASSWORD: postgres
 
-    # Add "forwardPorts": ["5432"] to **devcontainer.json** to forward PostgreSQL locally.
+    # Add "forwardPorts": [5432] to **devcontainer.json** to forward PostgreSQL locally.
     # (Adding the "ports" property to this file will not forward from a Codespace.)
 
 volumes: