Release 0.22.4

# History

## 0.22.4

Install/update via the bootstrap script:

```shell
wget https://raw.githubusercontent.com/dokku/dokku/v0.22.4/bootstrap.sh
sudo DOKKU_TAG=v0.22.4 bash bootstrap.sh
```

### Bug Fixes

- #4274: @josegonzalez Use correct warning message for deprecated code

### New Features

- #4273: @josegonzalez Upgrade to golang 1.15

### Refactors

- #4275: @josegonzalez Add calls to verify app name in subcommands

### Documentation

- #4272: @josegonzalez Correct help output for ssh-keys command

### Tests

- #4276: @josegonzalez Upgrade version of plugn used in tests

docs/development/release-process.md

@@ -29,7 +29,7 @@ The workflow looks like this:
 ```shell
 # having dokku-arch in ../dokku-arch
 vagrant up build-arch
-# wait for "==> build-arch: ==> Finished making: dokku 0.22.3-2 (Mon Feb 22 23:20:37 CET 2016)"
+# wait for "==> build-arch: ==> Finished making: dokku 0.22.4-2 (Mon Feb 22 23:20:37 CET 2016)"
 cd ../dokku-arch
 git add PKGBUILD .SRCINFO
 git commit -m 'Update to dokku 0.9.9'