Merge pull request #404 from opentripplanner/fix-pdf-import

Use import for pdfkit

Author: binh-dam-ibigroup

Diff for: lib/util/PDFDocumentWithTables.js

@@ -1,6 +1,6 @@
 'use strict'
 
-const PDFDocument = require('pdfkit')
+import PDFDocument from 'pdfkit'
 
 /**
  * This class extends the pdfkit functionality to provide a tables method, which