fix: use the process dir if PROJECT_ROOT does not exist

This can happen if you don’t go through fedx-scripts to use a config file.

Author: David Joy

lib/paths.js

@@ -1,6 +1,6 @@
 const path = require('path');
 
 module.exports = {
-  PROJECT_ROOT: process.env.PROJECT_ROOT,
+  PROJECT_ROOT: process.env.PROJECT_ROOT ? process.env.PROJECT_ROOT : process.cwd(),
   BASE_CONFIG_DIR: path.resolve(__dirname, '..', 'config'),
 };