Fix issue with the HOST variable during CI

[dat-adi]

As of right now, the GITEA_HOST variable in the .github/workflows/coverage.yml is hard coded into the file.
This has been done as there seems to be an error faced during the CI.

The current line should ideally be converted into,

DYNACONF_GITEA__HOST : ${{ secrets.DYNACONF_GITEA__HOST }}