chore: release 3.1.5 (#319)

🤖 I have created a release \*beep\* \*boop\*
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### [3.1.5](https://www.github.com/googleapis/nodejs-containeranalysis/compare/v3.1.4...v3.1.5) (2021-06-30)


### Bug Fixes

* make request optional in all cases ([#318](https://www.github.com/googleapis/nodejs-containeranalysis/issues/318)) ([35e8196](https://www.github.com/googleapis/nodejs-containeranalysis/commit/35e81964f971d4272b0c14f4e8b6e790229ba803))
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This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).

container-analysis/snippets/package.json

@@ -14,7 +14,7 @@
     "test": "mocha --timeout 100000 test/**.test.js"
   },
   "dependencies": {
-    "@google-cloud/containeranalysis": "^3.1.4",
+    "@google-cloud/containeranalysis": "^3.1.5",
     "@google-cloud/pubsub": "^2.0.0",
     "p-retry": "^4.1.0"
   },