Release 0.13.1

# History

## 0.13.1

Install/update via the bootstrap script:

```shell
wget https://raw.githubusercontent.com/dokku/dokku/v0.13.1/bootstrap.sh
sudo DOKKU_TAG=v0.13.1 bash bootstrap.sh
```

### Bug Fixes

- #3324: @josegonzalez Add missing source of config functions

contrib/dokku-installer.py

@@ -10,7 +10,7 @@ import subprocess
 import sys
 import threading
 
-VERSION = 'v0.13.0'
+VERSION = 'v0.13.1'
 
 hostname = ''
 try: