Fix Cache.warn function to issue a "config" warning
Fix Cache.warn function to issue a "config" warning

nicoddemus/pytest,hackebrot/pytest,txomon/pytest,tomviner/pytest,tomviner/pytest,The-Compiler/pytest,davidszotten/pytest,pytest-dev/pytest,alfredodeza/pytest,The-Compiler/pytest,ddboline/pytest,Akasurde/pytest,RonnyPfannschmidt/pytest,pfctdayelise/pytest,markshao/pytest,nicoddemus/pytest