[nginx] Changed README.md due to bug (wrong description) (CloudPirates-io#197)

Update README.md

Author: jmetzger

charts/nginx/README.md

@@ -57,7 +57,11 @@ To run Nginx on port 8080 with matching health checks:
 
 ```yaml
 # my-values.yaml
-containerPort: 8080
+containerPorts:
+- name: http
+  containerPort: 8080
+  protocol: TCP
+
 serverConfig: |
   server {
     listen 0.0.0.0:8080;