Collaborator list showing null values

[GbotemiB]

Checklist

• I am using the current main branch or the latest release. Please indicate.
• I am running on an up-to-date pypsa-earth environment. Update via conda env update -f envs/environment.yaml.

Describe the Bug

Please provide a description of what the bug is and add a minimal example/command for reproducing the bug.

Currently in the collaborators section, some users are showing null. I think it is because such users doesnt have a firstname and lastname to their github accounts, of which the github action responsible for the adding contributors uses firstname and lastname.

I think a quick fix will be to use username instead.

Error Message

If applicable, paste any terminal output to help illustrating your problem.
In some cases it may also be useful to share your list of installed packages: conda list.

<paste here>