Make ESCAPE_CHAR as static as in other classes (QuotedPrintableCodec, URLCodec)

Author: kinow

src/main/java/org/apache/commons/codec/net/PercentCodec.java

@@ -42,7 +42,7 @@ public class PercentCodec implements BinaryEncoder, BinaryDecoder {
      * The escape character used by the Percent-Encoding in order to introduce an encoded character.
      */
 
-    private final byte ESCAPE_CHAR = '%';
+    private static final byte ESCAPE_CHAR = '%';
 
     /**
      * The bit set used to store the character that should be always encoded