Fix double encoded targeting string in query string

Values in the targeting string can include comma (',') and we do not want to double encode those as we will encode again when we build the querystring with createQueryString().

modules/yieldlabBidAdapter.js

@@ -37,7 +37,7 @@ export const spec = {
     utils._each(validBidRequests, function (bid) {
       adslotIds.push(bid.params.adslotId)
       if (bid.params.targeting) {
-        query.t = createQueryString(bid.params.targeting)
+        query.t = createTargetingString(bid.params.targeting)
       }
       if (bid.userIdAsEids && Array.isArray(bid.userIdAsEids)) {
         query.ids = createUserIdString(bid.userIdAsEids)
@@ -198,6 +198,23 @@ function createQueryString (obj) {
   return str.join('&')
 }
 
+/**
+ * Creates an unencoded targeting string out of an object with key-values
+ * @param {Object} obj
+ * @returns {String}
+ */
+function createTargetingString (obj) {
+  let str = []
+  for (var p in obj) {
+    if (obj.hasOwnProperty(p)) {
+      let key = p
+      let val = obj[p]
+      str.push(key + '=' + val)
+    }
+  }
+  return str.join('&')
+}
+
 /**
  * Handles an outstream response after the library is loaded
  * @param {Object} bid