wis2box-management hangs on "pywis-topics bundle sync" when external access unavailable

[maaikelimper]

Troubleshooting Mexico I found the following issue:
their wis2box-management container hung in the /entrypoint on the line
pywis-topics bundle sync

To fix the problem Mexico will need to puncture holes in their firewall for:

    ZIPFILE_URL = 'https://wmo-im.github.io/wis2-topic-hierarchy/wth-bundle.zip'  
    IANA_URL = 'https://data.iana.org/TLD/tlds-alpha-by-domain.txt'

No errors were printed making the problem hard to detect

Can we change the implementation of "pywis-topic bundle sync" in wis2box to avoid hanging the container at startup ? And/or print an error to indicate the issue running this ?