Add issue guidelines to README
Add issue guidelines to README

TheMolkaPL/CardinalPGM,iPGz/CardinalPGM,Pablete1234/CardinalPGM,angelitorb99/CardinalPGM,Electroid/ExperimentalPGM,Aaron1011/CardinalPGM,Electroid/ExperimentalPGM,dentmaged/Cardinal-Plus,CaptainElliott/CardinalPGM,Alan736/NotCardinalPGM,SungMatt/CardinalPGM,twizmwazin/CardinalPGM,Alan736/NotCardinalPGM,dentmaged/Cardinal-Dev,TheMolkaPL/CardinalPGM,dentmaged/Cardinal-Plus,dentmaged/CardinalPGM,dentmaged/Cardinal-Dev,dentmaged/CardinalPGM