Spring Cloud Config Misleading variable name in 3.1.x AwsS3EnvironmentRepository

The name of variable json at line 146-147 seems misleading.

https://github.com/spring-cloud/spring-cloud-config/blob/85314467fe6a85de1ce4ad1fbd7e8a763204ab60/spring-cloud-config-server/src/main/java/org/springframework/cloud/config/server/environment/AwsS3EnvironmentRepository.java#L144-L153

Comment From: ryanjbaxter

If you would like to submit a PR that makes the variable name more clear, that would be great!