Update RunLengthEncoding.java

exercises/run-length-encoding/src/main/java/RunLengthEncoding.java

-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
 public class RunLengthEncoding {
     public String encode(String data) {
         throw new UnsupportedOperationException("Method has not been implemented yet.");
     public String decode(String encodedData) {
         throw new UnsupportedOperationException("Method has not been implemented yet.");
     }
-}
+}