Forced to use prefix on repository with multiple environments

[wilson1000-MoJ]

Hi CP.

Recently, I was forced to provide a prefix for ECR to write variables to GitHub environments. An issue occurred that prevented me from optimising my deployment script.

Problem
Even though GitHub environments were defined in the ECR module, the module persistently tried to write variables at the application repository level using the names ECR_REGION and ECR_ROLE_TO_ASSUME for each deployment, regardless of the configured github_environment.

This issue caused the ECR module to fail in concourse builds due to an inability to overwrite repository variables.

Solution
Prevent the ECR module from writing application repository-level variables when github_environment is set.