gitlab-ci: Build on Debian bullseye too

This gives us build coverage for something very similar to the
upcomfing Byzanthium Pureos release.
14 jobs for pureos-ci in 14 minutes and 19 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Build
passed #266043
librem5
api-visibility

00:02:43

passed #266047
librem5
build-debian-clang

00:03:19

passed #266045
librem5
build-debian-gcc-bullseye

00:03:27

passed #266044
librem5
build-debian-gcc-buster

00:03:28

passed #266048
librem5
build-fedora-gcc

00:03:04

passed #266046
librem5
build-pureos-gcc

00:02:59

 
  Test+Docs
passed #266049
librem5
build-gtkdoc

00:02:04

passed #266050
librem5
unit-test

00:01:59

41.1%
 
  Package
failed #266051
librem5
package-debian-buster

00:00:13

passed #266052
librem5:arm64
package-debian-buster:arm64

00:06:09

failed #266053
flatpak allowed to fail
package-flatpak

00:00:15

failed #266054
flatpak allowed to fail
package-flatpak-glade

00:00:15

 
  Test Package
skipped #266055
librem5
autopkgtest-debian-buster-package
skipped #266056
librem5
lintian-debian-buster-package
 
Name Stage Failure
failed
package-flatpak-glade Package
rm: cannot remove '_build/src/25a6634@@handy-1@sha/hdy-preferences-window.c.o': Permission denied
rm: cannot remove '_build/src/25a6634@@handy-1@sha/hdy-expander-row.c.gcno': Permission denied
rm: cannot remove '_build/src/25a6634@@handy-1@sha/hdy-combo-row.c.o': Permission denied
Uploading artifacts for failed job
Uploading artifacts...
_build/meson-logs/meson-log.txt: found 1 matching files

WARNING: sm.puri.Handy.Glade-dev.flatpak: no matching files
Uploading artifacts to coordinator... ok
id=266054 responseStatus=201 Created token=NemsV5Rj
ERROR: Job failed: exit code 1
failed
package-flatpak Package
rm: cannot remove '_build/src/25a6634@@handy-1@sha/hdy-application-window.c.gcda': Permission denied
rm: cannot remove '_build/src/25a6634@@handy-1@sha/hdy-preferences-page.c.o': Permission denied
rm: cannot remove '_build/src/25a6634@@handy-1@sha/hdy-preferences-window.c.gcno': Permission denied
Uploading artifacts for failed job
Uploading artifacts...
_build/meson-logs/meson-log.txt: found 1 matching files

WARNING: sm.puri.Handy.Demo-dev.flatpak: no matching files
Uploading artifacts to coordinator... ok
id=266053 responseStatus=201 Created token=WTRwWefw
ERROR: Job failed: exit code 1
failed
package-debian-buster Package There has been a runner system failure, please try again
Downloading artifacts for build-debian-gcc-bullseye (266045)...
Downloading artifacts from coordinator... ok
id=266045 responseStatus=200 OK token=MYvMz_xq
Downloading artifacts for build-debian-clang (266047)...
Downloading artifacts from coordinator... ok
id=266047 responseStatus=200 OK token=5R89PUxQ
Downloading artifacts for build-gtkdoc (266049)...
Downloading artifacts from coordinator... ok
id=266049 responseStatus=200 OK token=wx9qm4Pg
Downloading artifacts for unit-test (266050)...
Downloading artifacts from coordinator... ok
id=266050 responseStatus=200 OK token=8ByGLFWW
ERROR: Job failed (system failure): Error: No such container: 542e5a808c2c85003e65dd45cd411a622e460755e227db97730c14608af4e267 (executor_docker.go:783:0s)