fix typo for debug tag in README
fix typo for debug tag in README

davidbz/trafficserver,chitianhao/trafficserver,davidbz/trafficserver,chitianhao/trafficserver,SolidWallOfCode/trafficserver,persiaAziz/trafficserver,davidbz/trafficserver,persiaAziz/trafficserver,dyrock/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,pbchou/trafficserver,duke8253/trafficserver,davidbz/trafficserver,dyrock/trafficserver,vmamidi/trafficserver,chitianhao/trafficserver,persiaAziz/trafficserver,chitianhao/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,persiaAziz/trafficserver,vmamidi/trafficserver,persiaAziz/trafficserver,SolidWallOfCode/trafficserver,chitianhao/trafficserver,davidbz/trafficserver,dyrock/trafficserver,dyrock/trafficserver,chitianhao/trafficserver,chitianhao/trafficserver,persiaAziz/trafficserver,persiaAziz/trafficserver,davidbz/trafficserver,duke8253/trafficserver,pbchou/trafficserver,pbchou/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,bryancall/trafficserver,duke8253/trafficserver,vmamidi/trafficserver,SolidWallOfCode/trafficserver,dyrock/trafficserver,pbchou/trafficserver,bryancall/trafficserver,duke8253/trafficserver,persiaAziz/trafficserver,dyrock/trafficserver,duke8253/trafficserver,pbchou/trafficserver,vmamidi/trafficserver,dyrock/trafficserver,duke8253/trafficserver,pbchou/trafficserver,vmamidi/trafficserver