Update validate-snapshots.yml (#5357)

.github/workflows/validate-snapshots.yml

@@ -5,9 +5,12 @@ on:
     # Actions are scheduled in UTC
     # Until Actions supports timezones, we need to update this cron
     # twice a year (at the start and end of daylight saving time) 
-    # to account for daylight saving time in the UK
+    # to account for daylight saving time in the UK.
+    # Set a new reminder in the slack channel for next time to 
+    # change this
     # This action is intended to run at 9:35AM, 12:35PM & 4:35PM
-    - cron: '35 8,11,15 * * 1-5'
+    # March to October - cron: '35 8,11,15 * * 1-5'
+    - cron: '35 9,12,16 * * 1-5'
 env:
   GH_TOKEN: ${{ secrets.GH_TOKEN }}
   SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}