Update dns_desec.sh

ttl must be greater than or equal 3600, see https://desec.readthedocs.io/en/latest/dns/domains.html#domain-object

dnsapi/dns_desec.sh

@@ -61,7 +61,7 @@ dns_desec_add() {
   fi
   _debug txtvalues "$txtvalues"
   _info "Adding record"
-  body="[{\"subname\":\"$_sub_domain\", \"type\":\"TXT\", \"records\":[$txtvalues], \"ttl\":60}]"
+  body="[{\"subname\":\"$_sub_domain\", \"type\":\"TXT\", \"records\":[$txtvalues], \"ttl\":3600}]"
 
   if _desec_rest PUT "$REST_API/$DEDYN_NAME/rrsets/" "$body"; then
     if _contains "$response" "$txtvalue"; then