Generate Coverage Report in CI

[pascalkuthe]

I am striving for a high test coverage in nucleo. The matcher crate and the pattern parsing should already hit 80% test coverage. I would like to track coverage automatically in CI (for example with coveralls). This helps with triaging (identify uncovered branches) and makes it easier to track where tests are still needed.

I would imagine that we genrate test data with cargo tarpulin in CI and upload the report to coveralls or a similar service (I would need to setup the account once there is a PR). LLVM based instrumentation should be used.

[amaanq]

I can recommend cargo-llvm-cov