fix: [letsencrypt] allow all domains to be renewed in one go

Possibility to receive ``stdin`` in actions (a compose new feature)
introduced a bug here that would allow only the first domain to be
renewed.

Signed-off-by: Valentin Lab <valentin.lab@kalysto.org>

letsencrypt/lib/common

@@ -365,7 +365,7 @@ crt_renew() {
             else
                 info "Renewing domain $domain ($remaining days left)."
             fi
-            crt "$cfg" renew "$domain"
+            crt "$cfg" renew "$domain" </dev/null
             if [ "$?" != "0" ]; then
                 failed+=("$domain")
                 err "Certificate renew of '$domain' failed."