refactor: use set from lodash/fp instead of syntax

lib/ofac/update.js

@@ -137,7 +137,7 @@ function update () {
       const promiseNewEtags = Promise.resolve(ofacSources || [])
         .then(sources => Promise.all(_.map(promiseGetEtag, sources))
           .then(etags => _.map(
-            ([source, etag]) => ({...source, etag}),
+            ([source, etag]) => _.set('etag', etag,  source),
             _.zip(sources, etags)
           ))
         )