feat: normalize the outputFile path
feat: normalize the outputFile path

We used to this in Karma's config, but it really belongs here.

janeklb/karma-junit-reporter,karma-runner/karma-junit-reporter,patrot/karma-junit-test-spec-formatter,StoneCypher/karma-junit-reporter,actano/karma-jenkins-reporter,adriaanthomas/karma-junit-reporter,existentialism/karma-junit-reporter,SimenB/karma-junit-reporter,sethmcl/karma-junit-reporter,thescientist13/karma-junit-reporter,patrot/karma-junit-reporter,budde377/karma-junit-reporter,cesarandreu/karma-junit-reporter,tux4/karma-junit-reporter,robrich/karma-junit-reporter,killercentury/karma-junit-reporter,henriquegontijo/karma-junit-sonarqube-reporter,darksmile/karma-junit-reporter,mozimos/karma-junit-reporter,alexander-alvarez/karma-junit-reporter