update date extracting regex pattern + fix some strings in English

app/src/main/java/org/schabi/newpipe/Downloader.java

@@ -37,6 +37,7 @@ public class Downloader {
             HttpURLConnection con = (HttpURLConnection) url.openConnection();
             con.setRequestMethod("GET");
             con.setRequestProperty("User-Agent", USER_AGENT);
+            con.setRequestProperty("Accept-Language", "en");
 
             BufferedReader in = new BufferedReader(
                     new InputStreamReader(con.getInputStream()));