message: allow setting slack channel by env var
diff: @@ -14,7 +14,7 @@ xpack.notification:
  url: "${LOGSDB_SLACK_WEBHOOK_URL:https://hooks.slack.com/services/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}"
  message_defaults:
  from: "${LOGSDB_SLACK_USERNAME:x-pack}"
  - to: notifications
  + to: "${LOGSDB_SLACK_CHANNEL:#lagoon-dev-alerts}"
  attachment:
  fallback: "X-Pack Notification"
  color: "#a63636"
  