chore: update some envvar config (#1360)

* chore: decrease number of gunicorn workers from 8 to 4

too many workers -> high memory consumption and sigkill
we switch back to 4 workers

* chore: decrease PostgreSQL shared buffers size

We currently don't have enough RAM on VM 201 for 16 GB of shared buffers

.github/workflows/container-deploy.yml

@@ -134,12 +134,12 @@ jobs:
           echo "INFLUXDB_BUCKET=off_metrics" >> .env
           echo "INFLUXDB_AUTH_TOKEN=${{ secrets.INFLUXDB_AUTH_TOKEN }}" >> .env
           echo "SLACK_TOKEN=${{ secrets.SLACK_TOKEN }}" >> .env
-          echo "GUNICORN_NUM_WORKERS=8" >> .env
+          echo "GUNICORN_NUM_WORKERS=4" >> .env
           echo "EVENTS_API_URL=https://event.openfoodfacts.${{ env.ROBOTOFF_TLD }}" >> .env
           echo "IMAGE_MODERATION_SERVICE_URL=${{ env.IMAGE_MODERATION_SERVICE_URL }}" >> .env
 
           # PostgreSQL config
-          echo "ROBOTOFF_POSTGRES_SHARED_BUFFERS=16GB" >> .env
+          echo "ROBOTOFF_POSTGRES_SHARED_BUFFERS=8GB" >> .env
           echo "ROBOTOFF_POSTGRES_WORK_MEM=1GB" >> .env