Request OBS credentials to automatically fetch the repositories matching the latest Sailfish OS version

[HenkKalkwater]

Right now, the repos to base the site are hard-coded in the workflow file:

sailfishos-chum.github.io/.github/workflows/gen-site.yaml

Line 30 in 2a6e8d2

run: python -m chumweb --public-url "https://sailfishos-chum.github.io/" --repos 4.5.0.24_aarch64,4.5.0.24_i486,4.5.0.24_armv7hl --job-summary $GITHUB_STEP_SUMMARY

I'd rather use obs_user and obs_pass, so it fetches the repositories for the latest Sailfish OS version automatically, so no human is needed to update the GitHub workflow.

Tasks:

• Request new OBS credentials
• Modify the workflow
• Put the credentials in https://github.com/sailfishos-chum/sailfishos-chum.github.io/settings/secrets/actions