Merge #2958

2958: Upgrade to alpine 3.18.4 r=mergify[bot] a=nextgens

## What type of PR?

bug-fix

## What does this PR do?

Upgrade to alpine 3.18.4. This has a newer musl that fixes the DNS issue linked below.

I am not sure whether it would be wise to backport it to stable. We should discuss.

I mark it WIP for now as the mirror-image workflow is broken and CI will fail anyway.

### Related issue(s)
- close #2934
- close #2919

## 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.


Co-authored-by: Florent Daigniere <nextgens@freenetproject.org>
Co-authored-by: Dimitri Huisman <diman@huisman.xyz>

core/base/Dockerfile

@@ -3,7 +3,7 @@
 # base system image (intermediate)
 # Note when updating the alpine tag, first manually run the workflow .github/workflows/mirror.yml.
 # Just run the workflow with the tag that must be synchronised.
-ARG DISTRO=ghcr.io/mailu/alpine:3.17.2
+ARG DISTRO=ghcr.io/mailu/alpine:3.18.4
 FROM $DISTRO as system
 
 ENV TZ=Etc/UTC LANG=C.UTF-8

core/rspamd/start.py

@@ -37,4 +37,4 @@ while True:
 os.system("mkdir -m 755 -p /run/rspamd")
 os.system("chown rspamd:rspamd /run/rspamd")
 os.system("find /var/lib/rspamd | grep -v /filter | xargs -n1 chown rspamd:rspamd")
-os.execv("/usr/sbin/rspamd", ["rspamd", "-f", "-u", "rspamd", "-g", "rspamd"])
+os.execv("/usr/bin/rspamd", ["rspamd", "-f", "-u", "rspamd", "-g", "rspamd"])