chore: drop -g from npm install in ci config (#597)

Author: Rob--W

.circleci/config.yml

@@ -63,9 +63,9 @@ commands:
   run_test_bundlers:
     description: rerun unit tests on webpack and browserify bundled files
     steps:
-      - run: npm install -g browserify webpack webpack-cli
+      - run: npm install browserify webpack webpack-cli
       - run: |
-          export PATH=$PATH:../.npm-global/bin
+          export PATH=$PATH:$PWD/node_modules/.bin
           node ./scripts/run-module-bundlers-smoketests.js
 
   run_xephyr: