prod: garage: Enable on-demand-tls check for *.garage S3 endpoint

We were hitting Let's Encrypt rate limits because we were generating
thousands of non-sense certificates like "foo.bar.baz.garage.deuxfleurs.fr"

See https://crt.sh

Subdomains of garage.deuxfleurs.fr only make sense when accessing buckets
through S3 with vhost-style, so let's enable the on-demand-tls check to
make sure that the bucket exists in Garage.

In the long term, we might want to have a wildcard certificate for this
usage, or simply stop supporting vhost-style S3 access.

cluster/prod/app/garage/deploy/garage.hcl

@@ -104,6 +104,7 @@ job "garage" {
           "garage_api",
           "tricot garage.deuxfleurs.fr",
           "tricot *.garage.deuxfleurs.fr",
+          "tricot-on-demand-tls-ask http://garage-admin.service.prod.consul:3903/check",
           "tricot-site-lb",
         ]
         port = "s3"