The buster-backports repo is no longer available. This is preventing us from building any images that include his repo on apt-update failure
```
Get:1 http://security.debian.org buster/updates InRelease [34.8 kB]
Hit:2 http://apt.wikimedia.org/wikimedia buster-wikimedia InRelease
Hit:3 http://mirrors.wikimedia.org/debian buster InRelease
Hit:4 http://mirrors.wikimedia.org/debian buster-updates InRelease
Ign:5 http://mirrors.wikimedia.org/debian buster-backports InRelease
Err:6 http://mirrors.wikimedia.org/debian buster-backports Release
404 Not Found [IP: 208.80.154.74 8080]
Get:7 http://security.debian.org buster/updates/main amd64 Packages [595 kB]
Reading package lists...
E: The repository 'http://mirrors.wikimedia.org/debian buster-backports Release' no longer has a Release file.The command '/bin/sh -c apt-get update && apt-get install -y php7.4-tideways php7.4-ldap' returned a non-zero code: 100
make[1]: *** [Makefile:17: build-debug-image] Error 100
make[1]: Leaving directory '/srv/mwbuilder/release/make-container-image'
make: *** [Makefile:35: build-and-push-all-images] Error 2
make: Leaving directory '/srv/mwbuilder/release/make-container-image'
09:01:05 Finished build-and-push-container-images (duration: 00m 30s)
09:01:05 Build of K8s images failed (non-K8s deployment will continue normally)
```
According to [[ https://codesearch.wmcloud.org/search/?q=buster-backports&files=&excludeFiles=&repos= | CodeSearch ]], affected images are:
[] shellbox (lilypond and lilypond-data)
[] integration/config/operations-puppet (shellcheck)
[] integration/config/tox-buster (shellcheck)
[] integration/config/tox-pywikibot (shellcheck)
[] mediawiki/vagrant (php7.4-wikidiff2)
The base buster image also needs to have it removed, as it blocks all deployment of #mw-on-k8s on apt-update failure
[x] create component/lilypond and import the last version from buster-backports
[x] Rebuild base-images
[x] Rebuild buster-based production-images
[] Do a full rebuild deployment of mw-on-k8s `scap sync-world --k8s-only -D full_image_build:true `
[x] Restart `docker-reporter-base-images` and `docker-reporter-k8s-images`
[ ] Start docker-system-prune-all.service when the above two are done to clean up build2001