Fix memoize-one export issue

Author: praneshr

src/index.tsx

@@ -1,9 +1,11 @@
 import * as React from 'react'
 import * as diff from 'diff'
 import * as PropTypes from 'prop-types'
-import memoize from 'memoize-one'
 import cn from 'classnames'
 
+const m = require('memoize-one')
+const memoize = m.default || m
+
 import computeStyles, {
   IReactDiffViewerStyles,
   IReactDiffViewerStylesOverride,