make the map a private property

lib/src/sanitizer.dart

@@ -1,6 +1,6 @@
 part of validator;
 
-Map default_normalize_email_options = { 'lowercase': true };
+Map _default_normalize_email_options = { 'lowercase': true };
 
 
 // convert the input to a string
@@ -112,7 +112,7 @@ String escape(String str) {
 
 // canonicalize an email address
 String normalizeEmail(String email, [Map options]) {
-  options = _merge(options, default_normalize_email_options);
+  options = _merge(options, _default_normalize_email_options);
   if (isEmail(email) == false) {
       return '';
   }

pubspec.yaml

@@ -1,5 +1,5 @@
 name: validator
-version: 0.0.5
+version: 0.0.6
 author: Karan Goel <[email protected]>
 description: String validation and sanitization for Dart.
 homepage: https://github.com/karan/validator.dart