Added the signing secret.

Author: ocielliottc

.github/workflows/gradle-build-production.yml

@@ -87,6 +87,7 @@ jobs:
             --set-env-vars "^@^MICRONAUT_ENVIRONMENTS=cloud,google,gcp" \
             --set-env-vars "SLACK_WEBHOOK_URL=${{ secrets.SLACK_WEBHOOK_URL }}" \
             --set-env-vars "SLACK_BOT_TOKEN=${{ secrets.SLACK_BOT_TOKEN }}" \
+            --set-env-vars "SLACK_PULSE_SIGNING_SECRET=${{ secrets.SLACK_PULSE_SIGNING_SECRET }}" \
             --platform "managed" \
             --max-instances 8 \
             --allow-unauthenticated