Make NumberBuilder no longer Serializable

NumberBuilder holds onto a CharSequence rather than a specific concrete
implementation (like String). CharSequence is not Serializable, but
it needs to be if I want NumberBuilder to Serialize properly. In theory
I could make it Externalizable but I don't see the need so for now I'm
just removing Serializable from the declaration.

Author: dmaccormack

module/jsonurl-core/src/main/java/org/jsonurl/NumberBuilder.java

@@ -20,7 +20,6 @@
 import static org.jsonurl.CharUtil.digits;
 import static org.jsonurl.CharUtil.isDigit;
 
-import java.io.Serializable;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 
@@ -34,12 +33,7 @@
  * @author David MacCormack
  * @since 2019-09-01
  */
-public class NumberBuilder implements NumberText, Serializable {
-
-    /**
-     * serialVersionUID.
-     */
-    private static final long serialVersionUID = 1L;
+public class NumberBuilder implements NumberText {
 
     /**
      * The maximum number of digits I consider when parsing a