Improve logging by demoting warnings (#612)

Author: avalonche

services/api/service.go

@@ -1688,7 +1688,7 @@ func (api *RelayAPI) checkSubmissionSlotDetails(w http.ResponseWriter, log *logr
 func (api *RelayAPI) checkBuilderEntry(w http.ResponseWriter, log *logrus.Entry, builderPubkey phase0.BLSPubKey) (*blockBuilderCacheEntry, bool) {
 	builderEntry, ok := api.blockBuildersCache[builderPubkey.String()]
 	if !ok {
-		log.Warnf("unable to read builder: %s from the builder cache, using low-prio and no collateral", builderPubkey.String())
+		log.Infof("unable to read builder: %s from the builder cache, using low-prio and no collateral", builderPubkey.String())
 		builderEntry = &blockBuilderCacheEntry{
 			status: common.BuilderStatus{
 				IsHighPrio:    false,