Since this is a User repository, it is not possible to configure Pages to use a different source repository than master. So I had to update my workflow and set development as main branch. Another option might be pushing the artifacts to a separate repository and have Pages configured there.

The deployment is handled by a GitHub action workflow that will

• setup .NET
• build the application and publish it to the /build/ folder
• uses JamesIves/github-pages-deploy-action to deploy the code to the master branch