refactor: transform var to let/const (#60)

diff --git a/index.js b/index.js
index a5ebbea..8c22003 100644
--- a/index.js
+++ b/index.js
@@ -20,7 +20,7 @@
 // Entry point is needed so that the module could be required.
 // The module dir path will be needed to copy resources from it.
 
-var path = require('path');
+const path = require('path');
 
 module.exports = {
     dirname: path.join(__dirname, 'template_src')