Set the BUILDKITE_PLUGIN_S3_SECRETS_REGION var in the environment hook

Author: keithduncan

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

@@ -69,6 +69,7 @@ done
 
 if [[ -n "${BUILDKITE_SECRETS_BUCKET:-}" &&  "${SECRETS_PLUGIN_ENABLED:-}" == "1" ]] ; then
   export BUILDKITE_PLUGIN_S3_SECRETS_BUCKET="$BUILDKITE_SECRETS_BUCKET"
+  export BUILDKITE_PLUGIN_S3_SECRETS_REGION="$BUILDKITE_SECRETS_BUCKET_REGION"
 
   # shellcheck source=/dev/null
   source /usr/local/buildkite-aws-stack/plugins/secrets/hooks/environment

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

@@ -47,6 +47,7 @@ done
 
 if [[ -n "${BUILDKITE_SECRETS_BUCKET:-}" &&  "${SECRETS_PLUGIN_ENABLED:-}" == "1" ]] ; then
   export BUILDKITE_PLUGIN_S3_SECRETS_BUCKET="$BUILDKITE_SECRETS_BUCKET"
+  export BUILDKITE_PLUGIN_S3_SECRETS_REGION="$BUILDKITE_SECRETS_BUCKET_REGION"
 
   # shellcheck source=/dev/null
   source /usr/local/buildkite-aws-stack/plugins/secrets/hooks/environment