ci: add cppcheck

4 jobs for cppcheck in 3 minutes and 47 seconds
Name Stage Failure
build:source Build
make[2]: *** [gpu/CMakeFiles/villas-gpu.dir/build.make:96: gpu/CMakeFiles/villas-gpu.dir/src/] Error 1
make[2]: *** Waiting for unfinished jobs....
15 errors detected in the compilation of "/tmp/tmpxft_000002b6_00000000-6_gpu.cpp1.ii".
make[2]: *** [gpu/CMakeFiles/villas-gpu.dir/build.make:83: gpu/CMakeFiles/villas-gpu.dir/src/gpu.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:245: gpu/CMakeFiles/villas-gpu.dir/all] Error 2
make: *** [Makefile:172: all] Error 2
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1