Ensure AWS_ECR_LOGIN is passed into ECR plugin

Author: petetomasik

packer/linux/conf/buildkite-agent/hooks/environment

@@ -115,6 +115,11 @@ if [[ "${BUILDKITE_ECR_POLICY:-}" != "none" && "${ECR_PLUGIN_ENABLED:-}" == "1"
     export BUILDKITE_PLUGIN_ECR_ACCOUNT_IDS_0="${AWS_ECR_LOGIN_REGISTRY_IDS}"
   fi
 
+  # map AWS_ECR_LOGIN into the plugin format
+  if [[ -n "${AWS_ECR_LOGIN:-}" ]]; then
+    export BUILDKITE_PLUGIN_ECR_LOGIN="${AWS_ECR_LOGIN}"
+  fi
+
   # shellcheck source=/dev/null
   source /usr/local/buildkite-aws-stack/plugins/ecr/hooks/environment
 fi

packer/windows/conf/buildkite-agent/hooks/environment

@@ -61,6 +61,11 @@ if [[ "${BUILDKITE_ECR_POLICY:-}" != "none" && "${ECR_PLUGIN_ENABLED:-}" == "1"
     export BUILDKITE_PLUGIN_ECR_ACCOUNT_IDS_0="${AWS_ECR_LOGIN_REGISTRY_IDS}"
   fi
 
+  # map AWS_ECR_LOGIN into the plugin format
+  if [[ -n "${AWS_ECR_LOGIN:-}" ]]; then
+    export BUILDKITE_PLUGIN_ECR_LOGIN="${AWS_ECR_LOGIN}"
+  fi
+
   # shellcheck source=/dev/null
   source /usr/local/buildkite-aws-stack/plugins/ecr/hooks/environment
 fi