Update dependency @google-cloud/bigquery to v0.12.0

Author: renovate[bot]

functions/sendgrid/package.json

@@ -17,7 +17,7 @@
     "test": "ava -T 20s --verbose test/*.test.js"
   },
   "dependencies": {
-    "@google-cloud/bigquery": "0.10.0",
+    "@google-cloud/bigquery": "0.12.0",
     "@google-cloud/storage": "1.4.0",
     "safe-buffer": "5.1.1",
     "sendgrid": "5.2.3",