Coverage of develop

No coverage report for develop yet.

Give a job in .flow/pipeline.kdl an artifact named coverage holding an LCOV report, and the hub reads it when the job uploads it. For Rust:

job "coverage" {
    sandbox "rust"
    exec "cargo" "llvm-cov" "--workspace" "--lcov" "--output-path" "/src/target/lcov.info"
    output {
        artifact "coverage" { path "/src/target/lcov.info" }
    }
}

Istanbul (--reporter=lcov), coverage.py (coverage lcov) and gcov with lcov write LCOV too; Cobertura XML (coverage xml, Coverlet) and JaCoCo XML (Gradle's jacocoTestReport, Kover) are read as well. Paths are read relative to the job's /src; a JaCoCo path, relative to its source root, is found by its ending.