Release 0.15.3

# History

## 0.15.3

Install/update via the bootstrap script:

```shell
wget https://raw.githubusercontent.com/dokku/dokku/v0.15.3/bootstrap.sh
sudo DOKKU_TAG=v0.15.3 bash bootstrap.sh
```

### New Features

- #3489: @josegonzalez feat: upgrade herokuish to 0.5.0 (Ubuntu 18.04)

docs/assets/versions.json

@@ -12,6 +12,6 @@
     "0.12.13",
     "0.13.4",
     "0.14.6",
-    "0.15.2"
+    "0.15.3"
   ]
 }