CI: add check for REUSE

        - tar cfz cov-int.tar.gz cov-int

        - curl --form token=$COVERITY_SCAN_TOKEN --form email=$GITLAB_USER_EMAIL --form file=@cov-int.tar.gz --form version="`git describe --tags`" --form description="`git describe --tags` / $CI_COMMIT_TITLE / $CI_COMMIT_REF_NAME:$CI_PIPELINE_ID " https://scan.coverity.com/builds?project=$COVERITY_SCAN_PROJECT_NAME

fmt:reuse:

    image:

        name: fsfe/reuse:latest

        entrypoint: [""]

    tags:

      - docker

    stage: formatting

    needs: []

    dependencies: []

    script:

        - reuse lint

##############

# Unit tests #