chore(readme): correct a typo
chore(readme): correct a typo

Closes #51

benderTheCrime/karma-sc-haml2html-preprocessor,aorielly/karma-ng-html2js-preprocessor,thescientist13/karma-ng-html2js-preprocessor,marthinus-engelbrecht/karma-ng-html2js-preprocessor,benderTheCrime/karma-sc-haml2html-preprocessor,benderTheCrime/karma-sc-haml2html-preprocessor,karma-runner/karma-ng-html2js-preprocessor