[YouTube] Use final when possible

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeStreamExtractor.java

@@ -253,7 +253,8 @@ public class YoutubeStreamExtractor extends StreamExtractor {
      */
     @Override
     public long getTimeStamp() throws ParsingException {
-        long timestamp = getTimestampSeconds("((#|&|\\?)t=\\d{0,3}h?\\d{0,3}m?\\d{1,3}s?)");
+        final long timestamp =
+                getTimestampSeconds("((#|&|\\?)t=\\d{0,3}h?\\d{0,3}m?\\d{1,3}s?)");
 
         if (timestamp == -2) {
             // regex for timestamp was not found