refactor: update nodejs-common and google-auth-library (#112)

Author: JustinBeckwith

.circleci/config.yml

@@ -84,7 +84,6 @@ jobs:
           command: |-
             mkdir -p /home/node/.npm-global
             npm install
-            npm link
             chmod +x node_modules/@google-cloud/nodejs-repo-tools/bin/tools
           environment:
             NPM_CONFIG_PREFIX: /home/node/.npm-global
@@ -127,9 +126,8 @@ jobs:
           name: Link the module being tested to the samples.
           command: |
             cd samples/
-            npm link @google-cloud/datastore
+            npm link ../
             npm install
-            npm link @google-cloud/datastore
             cd ..
           environment:
             NPM_CONFIG_PREFIX: /home/node/.npm-global