Peter M. Groen / CLI11

* add some warning for GCC output

* fix some warnings

* style: pre-commit.ci fixes

* update ubuntu image used for cmake tests so it doesn't auto transition to 22.04

* try a few more warning flags

* install the correct files

* style: pre-commit.ci fixes

* fix install files

* add a few more things to pre-commit

* try a fix for codacy

* another try at codecov

* more coverage tweaks

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

* Adding first try at coverage

* Fix for CMakeLists

* Fix for wrong shell

* Fixes to Coverage

* Fix for missing coverage

* Adding badge

* Using repo token

* Adding test files to coverage

* Fix typo

* Adding codecov

* Fix for code coverage

* Fix single file tests under CodeCov

* Seperating coverage steps

* Fix testrunner to be ctest

* Fix constant rebuilding of doxygen

* Adding coverage, tested locally

* Adding compiler version to gcov

* Fixing code coverage gcov download and use

* Adding Coverage build type with some fixes

* Better way of using gcc

* Adding coverage badge

* Removing tests from calcs