Update scale-app.md

Author: Greedygre

articles/container-apps/scale-app.md

@@ -215,6 +215,7 @@ az containerapp create \
   --min-replicas 0 \
   --max-replicas 5 \
   --transport tcp \
+  --ingress <external/internal> \
   --target-port <CONTAINER_TARGET_PORT> \
   --scale-rule-name azure-tcp-rule \
   --scale-rule-type tcp \