Malformed sequence in publiccode.yml

At European Commission, we've implemented an Open Source Software Catalogue for public administrations. We are fetching data from member states catalogues based on publiccode.yml. See https://interoperable-europe.ec.europa.eu/eu-oss-catalogue/solutions. We hit an error trying to fetch this repository because of an error in your publiccode.yml. The usedBy sequence should wrap each item in quotes, otherwise each line is considered a map.

This part...

usedBy:
  - Beteiligungsportal der Stadt Ulm: beteiligedich.ulm.de
  - Beteiligungsportal der Stadt Köln: meinungfuer.koeln

...is interpreted by the YAML as:

usedBy:
  -
    Beteiligungsportal der Stadt Ulm: beteiligedich.ulm.de
  -
    Beteiligungsportal der Stadt Köln: meinungfuer.koeln

See https://yaml.org/spec/1.2.2/#22-structures, "Example 2.12 Compact Nested Mapping"

Correct representation would be:

usedBy:
  - 'Beteiligungsportal der Stadt Ulm: beteiligedich.ulm.de'
  - 'Beteiligungsportal der Stadt Köln: meinungfuer.koeln'

Thank you!