Fix test_receive.py date parsing wrt. Python3.6 used in CICD

Signed-off-by: Marcel Parciak <marcel.parciak@gmail.com>
4 jobs for dev in 6 minutes and 59 seconds (queued for 1 second)
Name Stage Failure
failed
dryrun_publish_to_harbor Test
Fetching changes with git depth set to 50...
Reinitialized existing Git repository in /home/gitlab-runner/builds/KR54QkSr/0/medinfpub/umg-medic/aw-agents/annotation-agent/.git/
Checking out 81389f1e as dev...
Skipping Git submodules setup
Executing "step_script" stage of the job script
$ docker login --username marcelparciak --password $HARBOR_PUSH_TOKEN https://harbor.umg.eu
WARNING! Using --password via the CLI is insecure. Use --password-stdin.
Error response from daemon: Get https://harbor.umg.eu/v2/: unauthorized: authentication required
ERROR: Job failed: exit status 1