Merge #3240

3240: Fix purge_user.sh (backport #3239) r=mergify[bot] a=mergify[bot]

## What type of PR?

bug-fix

## What does this PR do?

Fix purge_user.sh; thanks to [nike7o0](https://github.com/nike7o0)

### Related issue(s)
- close #3238 
- #2858

## Prerequisites
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- [ ] In case of feature or enhancement: documentation updated accordingly
- [x] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/workflow.html#changelog) entry file.
<hr>This is an automatic backport of pull request #3239 done by [Mergify](https://mergify.com).

Co-authored-by: Florent Daigniere <nextgens@freenetproject.org>

scripts/purge_user.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 
 # get id of running admin container
-admin="$(docker compose ps admin --format=json | jq -r '.[].ID')"
+admin="$(docker compose ps admin --format=json | jq -r '.ID')"
 if [[ -z "${admin}" ]]; then
 	echo "Sorry, can't find running mailu admin container."
 	echo "You need to start this in the path containing your docker-compose.yml."

towncrier/newsfragments/3238.bugfix

@@ -0,0 +1 @@
+Fix purge_user.sh