chore(main): release 3.1.2 (#345)

* chore(main): release 3.1.2

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>
Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: release-please[bot]

cloudbuild/package.json

@@ -15,7 +15,7 @@
     "test": "c8 mocha system-test --timeout=800000"
   },
   "dependencies": {
-    "@google-cloud/cloudbuild": "^3.1.1"
+    "@google-cloud/cloudbuild": "^3.1.2"
   },
   "devDependencies": {
     "c8": "^7.0.0",