The gitlab-ci generates errors

[ClausKlein]

see https://gitlab.com/ClausKlein/cpp_vcpkg_project/-/jobs/4959646661#L2011

(WARNING) Unrecognized GCOV output for /builds/ClausKlein/cpp_vcpkg_project/my_header_lib/test/constexpr/constexpr_tests.cpp
	  branch 58 never executed (fallthrough)
	  branch 59 never executed (throw)
	  branch 61 never executed (fallthrough)
	  branch 62 never executed (throw)
	This is indicative of a gcov output parse error.
	Please report this to the gcovr developers
	at <https://github.com/gcovr/gcovr/issues>.
(WARNING) Exception during parsing:

[ClausKlein]

This MR would fix it