Change Docker base image to 20.04

1 job for ubuntu-20-04-container in 12 seconds (queued for 1 second)
latest
Name Stage Failure
failed
e2e-test Test
  File "/usr/bin/trigger", line 407, in <module>
trigger(sys.argv[1:])
File "/usr/bin/trigger", line 350, in trigger
pid = create_pipeline(project_url, pipeline_token, ref, verifyssl, variables, verbose)
File "/usr/bin/trigger", line 108, in create_pipeline
assert r.status_code == 201, f'Failed to create pipeline, api returned status code {r.status_code}'
AssertionError: Failed to create pipeline, api returned status code 400
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1