[SoundCloud] Use api-v2 in SubscriptionExtractor

Also added

extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudSubscriptionExtractor.java

@@ -36,7 +36,7 @@ public class SoundcloudSubscriptionExtractor extends SubscriptionExtractor {
             throw new InvalidSourceException(e);
         }
 
-        String apiUrl = "https://api.soundcloud.com/users/" + id + "/followings"
+        String apiUrl = "https://api-v2.soundcloud.com/users/" + id + "/followings"
                 + "?client_id=" + SoundcloudParsingHelper.clientId()
                 + "&limit=200";
         ChannelInfoItemsCollector collector = new ChannelInfoItemsCollector(service.getServiceId());