[cppcheck] Run job only if needed

Ie. run only if a change to *.c *.h *.cpp *.hpp or *.ipp files where made

This can save some CI ressources for cases where eg. only README.md was changed

I don't know if this finally makes sense or if I miss something??? But I just came across the rules:changes and thought, even if it does not make a difference from a technical perceptive at least from a KDE Eco perceptive it makes sense.