Extract mono_ids in the correct way.

1 job for update-ctapipe-v0.12 in 7 seconds (queued for 4 seconds)
Name Stage Failure
run_tests Test
deb-src http://archive.debian.org/debian/ jessie main
deb http://security.debian.org jessie/updates main
deb-src http://security.debian.org jessie/updates main
deb http://ftp.de.debian.org/debian testing main
$ apt-get update -qq
W: GPG error: http://archive.debian.org/debian jessie Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8B48AD6246925553 NO_PUBKEY 7638D0442B90D010 NO_PUBKEY CBF8D6FD518E17E1
E: The repository 'http://archive.debian.org/debian jessie Release' is not signed.
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1