Update incorrect param name in trustedBiddingSignals URL example (#734)

FLEDGE.md

@@ -465,7 +465,7 @@ Buyers have three basic jobs in the on-device ad auction:
 
 Buyers may want to make on-device decisions that take into account real-time data (for example, the remaining budget of an ad campaign).  This need can be met using the interest group's `trustedBiddingSignalsURL` and `trustedBiddingSignalsKeys` fields.  Once a seller initiates an on-device auction on a publisher page, the browser checks each participating interest group for these fields, and makes an uncredentialed (cookieless) HTTP fetch to a URL of the form:
 
-    https://www.kv-server.example/getvalues?hostname=publisher.com&experimentGroupId=12345&keys=key1,key2&interestGroups=name1,name2
+    https://www.kv-server.example/getvalues?hostname=publisher.com&keys=key1,key2&interestGroupNames=name1,name2&experimentGroupId=12345
 
 The base URL `https://www.kv-server.example/getvalues` comes from the interest group's `trustedBiddingSignalsURL`, the hostname of the top-level webpage where the ad will appear `publisher.com` is provided by the browser, `experimentGroupId` comes from `perBuyerExperimentGroupIds` if provided, `keys` is a list of `trustedBiddingSignalsKeys` strings, and `interestGroupNames` is a list of the names of the interest groups that data is being fetched for.  The requests may be coalesced (for efficiency) across any number of interest groups that share a `trustedBiddingSignalsURL` (which means they also share an owner).