Add PR number to YAML metadata

Author: zigpy-bot

images/develco/1015-0391-00020004_748757.ota.yaml

@@ -2,5 +2,6 @@
 file_name: 1015-0391-00020004_748757.ota
 source_file_name: SmartButton_2.0.4.zigbee
 source_url: https://raw.githubusercontent.com/Develco-Products/frient_upgrade_images/main/SmartButton_2.0.4.zigbee
+pull_request: 84
 release_notes: |-
   - Battery measurement improvements