Removed image ubuntu in yml

2 jobs for pages in 53 seconds (queued for 2 seconds)
Name Stage Failure
build_dep Build
Get:3 jessie Release.gpg [2420 B]
Get:4 jessie Release [148 kB]
Get:5 jessie/updates/main amd64 Packages [866 kB]
Get:6 jessie/main amd64 Packages [9098 kB]
Fetched 10.2 MB in 27s (366 kB/s)
W: Failed to fetch Unable to find expected entry 'main/binary-amd64/Packages' in Release file (Wrong sources.list entry or malformed file)

E: Some index files failed to download. They have been ignored, or old ones used instead.
ERROR: Job failed: exit code 1