Commit 00f12220c08a6e5fd2a4e5eef6ca0cf34b4a7b5b broke the cppcheck job
in GitLab CI: when cppcheck fails, the script is immediately
interrupted, preventing cppcheck-htmlreport from being run. To ensure
the HTML report is generated when cppcheck fails, revert to invoking
cppcheck-htmlreport in the "after_script" part of the job.