ci: Switch to crimson

.gitlab-ci.yml

-include:
- - 'https://source.puri.sm/Librem5/librem5-ci/raw/master/librem5-pipeline-definitions.yml'
- - 'https://source.puri.sm/Librem5/librem5-ci/raw/master/librem5-pipeline-byzantium-jobs.yml'
+variables:
+    L5_DOCKER_IMAGE: pureos/pureos:landing
 
-before_script:
- - echo "deb http://repo.pureos.net/pureos landing main" >> /etc/apt/sources.list.d/landing.list
- - apt-get update
+include:
+ - 'https://source.puri.sm/guido.gunther/librem5-ci/raw/master/librem5-pipeline-definitions.yml'
+ - 'https://source.puri.sm/guido.gunther/librem5-ci/raw/master/pureos-packaging-ci.yml'
 
 stages:
  - test
@@ -12,7 +11,7 @@ stages:
  - test-package
 
 shellcheck:
- image: debian:bullseye
+ image: $L5_DOCKER_IMAGE
  before_script:
     - echo
  tags: