bump version to 0.13.6

CloudronManifest.json

@@ -4,7 +4,7 @@
   "author": "Gogs developers",
   "description": "file://DESCRIPTION.md",
   "tagline": "A painless self-hosted Git Service",
-  "version": "0.13.5",
+  "version": "0.13.6",
   "healthCheckPath": "/healthcheck",
   "httpPort": 3000,
   "addons": {