updated readme.md
updated readme.md

Changed instruction that `deregister_from_elb.sh` should be run on BeforeInstall hook to the ApplicationStop hook
yyolk/aws-codedeploy-samples,KCFTech/aws-codedeploy-samples,oba11/aws-codedeploy-samples,jimblesm/aws-codedeploy-samples,yyolk/aws-codedeploy-samples,mpantelimon/aws-codedeploy-samples,AlphaStaxLLC/aws-codedeploy-samples,yyolk/aws-codedeploy-samples,bluespurs/aws-codedeploy-samples,yyolk/aws-codedeploy-samples,jimblesm/aws-codedeploy-samples,AlphaStaxLLC/aws-codedeploy-samples,pradhmanyu/aws-codedeploy-samples,akashrchoksi/codedeploy,KCFTech/aws-codedeploy-samples,jimblesm/aws-codedeploy-samples,oba11/aws-codedeploy-samples,mpantelimon/aws-codedeploy-samples,akashrchoksi/codedeploy,alexdglover/aws-codedeploy-samples,mpareja/aws-codedeploy-samples,akashrchoksi/codedeploy,mpareja/aws-codedeploy-samples,Blackbaud-ThomasNguyen/aws-codedeploy-samples,pradhmanyu/aws-codedeploy-samples,yyolk/aws-codedeploy-samples,mpareja/aws-codedeploy-samples,alexdglover/aws-codedeploy-samples,KCFTech/aws-codedeploy-samples,jimblesm/aws-codedeploy-samples,Blackbaud-ThomasNguyen/aws-codedeploy-samples,bluespurs/aws-codedeploy-samples,bluespurs/aws-codedeploy-samples,mpareja/aws-codedeploy-samples,AlphaStaxLLC/aws-codedeploy-samples,bluespurs/aws-codedeploy-samples,oba11/aws-codedeploy-samples,AlphaStaxLLC/aws-codedeploy-samples,oba11/aws-codedeploy-samples,pradhmanyu/aws-codedeploy-samples,mpantelimon/aws-codedeploy-samples,mpantelimon/aws-codedeploy-samples,akashrchoksi/codedeploy,mpareja/aws-codedeploy-samples,akashrchoksi/codedeploy,pradhmanyu/aws-codedeploy-samples,alexdglover/aws-codedeploy-samples,Blackbaud-ThomasNguyen/aws-codedeploy-samples,oba11/aws-codedeploy-samples,alexdglover/aws-codedeploy-samples,KCFTech/aws-codedeploy-samples,mpantelimon/aws-codedeploy-samples,pradhmanyu/aws-codedeploy-samples,AlphaStaxLLC/aws-codedeploy-samples,Blackbaud-ThomasNguyen/aws-codedeploy-samples,Blackbaud-ThomasNguyen/aws-codedeploy-samples,KCFTech/aws-codedeploy-samples,bluespurs/aws-codedeploy-samples,jimblesm/aws-codedeploy-samples,alexdglover/aws-codedeploy-samples