Release 0.21.4

# History

## 0.21.4

Install/update via the bootstrap script:

```shell
wget https://raw.githubusercontent.com/dokku/dokku/v0.21.4/bootstrap.sh
sudo DOKKU_TAG=v0.21.4 bash bootstrap.sh
```

### Bug Fixes

- #4092: @Yihao-G Fix nginx proxy-read-timeout not set for HTTPS
- #4095: @GennadySpb Fix application removal during uninstallation

### New Features

- #4097: @josegonzalez Update herokuish

### Documentation

- #4096: @josegonzalez Clarify that special config variables are not exposed to applications
- #4007: @turicas Clarify nginx.conf.sigil path in image when deploying non-buildpack apps
- #4078: @gurpreetatwal Add more details to `nginx-dokku-template-source` trigger
- #4090: @ankane Official plugins no longer in beta
- #4085: @josegonzalez Set warning on resource type as an actual warning

### Other

- #4082: @dependabot-preview[bot] chore(deps): bump monolog/monolog from 1.25.4 to 1.25.5 in /tests/apps/php

plugins/shell/plugin.toml

@@ -1,4 +1,4 @@
 [plugin]
 description = "dokku core shell plugin"
-version = "0.21.3"
+version = "0.21.4"
 [plugin.config]