Added reminder to not enable APIGW cache during workshop to keep costs lower for participants

Author: kylesomers

README.md

@@ -54,7 +54,7 @@ Tokyo (ap-northeast-1) | [![Launch Zombie Workshop Stack into Tokyo with CloudFo
 
 **The baseline chat application is now configured and working! There is still important functionality missing and the Lambda Signal Corps needs you to build it out...so get started below!**
 
-*This workshop does not utilize API Gateway Cache. Please KEEP THIS FEATURE TURNED OFF as it is not covered under the AWS Free Tier and will incur additional charges.*
+*This workshop does not utilize API Gateway Cache. Please KEEP THIS FEATURE TURNED OFF as it is not covered under the AWS Free Tier and will incur additional charges. It is not a requirement for the workshop.*
 
 ## Lab 1 - Typing Indicator