tests: run mvdan/shfmt on test runs

While I do not agree with _every_ style change, this will force Dokku to have consistent formatting across all shell scripts, which is arguably a Good Thing™.

The command used to reprocess everything is:

```shell
shfmt -l -bn -ci -i 2 -w .
```

plugins/apps/subcommands/unlock

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
-set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
 source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
 source "$PLUGIN_AVAILABLE_PATH/apps/internal-functions"
 
@@ -7,11 +8,12 @@ apps_unlock_cmd() {
   declare desc="unlocks an app for deployment"
   declare cmd="apps:unlock"
   [[ "$1" == "$cmd" ]] && shift 1
-  declare APP="$1"; verify_app_name "$APP"
+  declare APP="$1"
+  verify_app_name "$APP"
 
   if [[ -f "$DOKKU_ROOT/$APP/.deploy.lock" ]]; then
-  	dokku_log_warn "A deploy may be in progress."
-  	dokku_log_warn "Removing the app lock will not stop in progress deploys."
+    dokku_log_warn "A deploy may be in progress."
+    dokku_log_warn "Removing the app lock will not stop in progress deploys."
   fi
 
   rm -f "$DOKKU_ROOT/$APP/.deploy.lock" || dokku_log_fail "Unable to remove deploy lock"