Fixing Github Actions Workflow

[SebGoliot]

This fixes the issue #221

• GITHUB_TOKEN was missing
• ubuntu-latest is missing the importlib-metadata package, as it is not required since Python 3.8
• Dsonar.host.url was missing
• Dsonar.sources had a typo (Blask instead of blask)
• Updated the setup-sonar-scanner action to v3

I also had to edit the pipfile, changed the python version from python 3.7 to 3.7,
But it may be a good idea to set it to 3, as it should solve the issue #220 (see #222)