logs: lower no digest from warn to info

lib/manager/docker/package.js

@@ -10,6 +10,7 @@ module.exports = {
 
 async function getPackageUpdates(config) {
   const {
+    currentFrom,
     dockerRegistry,
     depName,
     currentDepTag,
@@ -27,8 +28,8 @@ async function getPackageUpdates(config) {
       currentTag
     );
     if (!newDigest) {
-      logger.warn(
-        { dockerRegistry, depName, currentTag },
+      logger.info(
+        { currentFrom, dockerRegistry, depName, currentTag },
         'Dockerfile no digest'
       );
       return [];