Update tag used by nginx-proxy-manager-v3 (#463)

Updating [NGINX-Proxy-Manager](https://github.com/NginxProxyManager/nginx-proxy-manager) to the [`:v3`](https://registry.hub.docker.com/layers/jc21/nginx-proxy-manager/v3/images/sha256-431328a323e7237499b1e80578221734f5e279469e519faed3c41f663b352968) tag, as `:v3-develop` is no longer available.

template/apps/nginx-proxy-manager-v3.json

@@ -21,9 +21,9 @@
 			"name": "TZ"
 		}
 	],
-        "image_arm32": "jc21/nginx-proxy-manager:v3-develop",
-        "image_arm64": "jc21/nginx-proxy-manager:v3-develop",
-        "image_amd64": "jc21/nginx-proxy-manager:v3-develop",
+        "image_arm32": "jc21/nginx-proxy-manager:v3",
+        "image_arm64": "jc21/nginx-proxy-manager:v3",
+        "image_amd64": "jc21/nginx-proxy-manager:v3",
 	"logo": "https://raw.githubusercontent.com/pi-hosted/pi-hosted/master/images/proxy_mgr.png",
 	"name": "nginx-proxy-manager-v3",
 	"officialDoc": "https://nginxproxymanager.com/setup/",