Change output type to `cobertura`

  image: rust:latest

  variables:

    RUSTFLAGS: "-Zinstrument-coverage"

    LLVM_PROFILE_FILE: "coverage-%p-%m.profraw"

    LLVM_PROFILE_FILE: "arti-%p-%m.profraw"

  script:

    - rustup toolchain add nightly

    - rustup default nightly

    - rustup component add llvm-tools-preview

    - apt-get update && apt-get install -y lcov python3-pip python3-setuptools

    - cargo test --verbose --target x86_64-unknown-linux-gnu --all-features

    # generate html report

    - cargo install grcov

    - grcov . --binary-path ./target/x86_64-unknown-linux-gnu/ -s . -t html --branch --ignore-not-existing --ignore "*cargo*" -o ./coverage/

    # generate cobertura report for gitlab integration

    - pip3 install lcov_cobertura

    - grcov . --binary-path ./target/x86_64-unknown-linux-gnu/ -s . -t lcov --branch --ignore-not-existing --ignore "*cargo*" -o coverage.lcov

    - pip3 show lcov_cobertura

    - python3 /usr/local/lib/python3.9/dist-packages/lcov_cobertura.py coverage.lcov

    - grcov . --binary-path ./target/x86_64-unknown-linux-gnu/ -s . -t cobertura --branch --ignore-not-existing --ignore "*cargo*" -o coverage.xml

    # output coverage summary for gitlab parsing

    - lcov --summary coverage.lcov

    - apt-get update && apt-get install -y lcov

    - lcov --summary coverage.xml

  artifacts:

    paths:

      - 'coverage'