This saves two build-jobs from performing the same (expensive!)
compilation+installation over and over again, when it is much cheaper to
cache it in the image instead.
grcov 0.8.0 now has cobertura support so we no longer need to to export
to lcov format and then convert.
Extract the summary from the generated html so the metric matches the
one from the html report (for some reason the cobertura ones are
differents).
The new gitlab summary parsing regexp is now:
<abbr .*>(\d+.\d+) %<\/abbr>
It's been replaced by cargo-deny in all modules.
Don't regenerate images for now, it's not a problem to keep it around
until the next images update round.
CARGO_HOME's semantic depends on when it's used in the pipeline:
- it's the install prefix when installing Cargo
- it's the crate cache location when building jobs
env.sh is sourced at the start of all jobs and was overidding the
CARGO_HOME path defined in the CI template for caching. Fix this by
moving the prefix install path to install-rust.sh.
