fix(utilities): allow numbers in custom style names

Author: samikarak

lib/utilities.js

@@ -1,6 +1,6 @@
 var React = require('react');
 var hyphenPatternRegex = /-([a-z])/g;
-var CUSTOM_PROPERTY_OR_NO_HYPHEN_REGEX = /^--[a-zA-Z-]+$|^[^-]+$/;
+var CUSTOM_PROPERTY_OR_NO_HYPHEN_REGEX = /^--[a-zA-Z0-9-]+$|^[^-]+$/;
 
 /**
  * Converts a string to camelCase.

test/utilities.js

@@ -22,6 +22,8 @@ describe('utilties.camelCase', () => {
     assert.equal(camelCase('fooBar'), 'fooBar');
     assert.equal(camelCase('--fooBar'), '--fooBar');
     assert.equal(camelCase('--foo-bar'), '--foo-bar');
+    assert.equal(camelCase('--foo100'), '--foo100');
+    assert.equal(camelCase('--foo-100'), '--foo-100');
   });
 
   it('camelCases a string', () => {