Release 0.19.6

# History

## 0.19.6

Install/update via the bootstrap script:

```shell
wget https://raw.githubusercontent.com/dokku/dokku/v0.19.6/bootstrap.sh
sudo DOKKU_TAG=v0.19.6 bash bootstrap.sh
```

### Other

- #3761: @pithyless Fix type-errors in dokku-installer.py
- #3759: @dependabot-preview[bot] chore(deps-dev): bump heroku/heroku-buildpack-php from 163 to 164 in /tests/apps/php
- #3758: @dependabot-preview[bot] chore(deps): bump jetty-servlet from 9.4.21.v20190926 to 9.4.22.v20191022 in /tests/apps/java

contrib/dokku-installer.py

@@ -14,7 +14,7 @@ import subprocess
 import sys
 import threading
 
-VERSION = 'v0.19.5'
+VERSION = 'v0.19.6'
 
 def bytes_to_string(b):
     if type(b) == bytes: