chore: release 3.1.3 (#154)

🤖 I have created a release \*beep\* \*boop\*
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### [3.1.3](https://www.github.com/googleapis/nodejs-service-directory/compare/v3.1.2...v3.1.3) (2021-06-23)


### Bug Fixes

* make request optional in all cases ([#153](https://www.github.com/googleapis/nodejs-service-directory/issues/153)) ([3bc4004](https://www.github.com/googleapis/nodejs-service-directory/commit/3bc4004be93fadaf15b84c7aea31eba3450ddd8d))
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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).

service-directory/snippets/package.json

@@ -13,7 +13,7 @@
     "test": "c8 mocha --timeout 600000 test/*.js"
   },
   "dependencies": {
-    "@google-cloud/service-directory": "^3.1.2",
+    "@google-cloud/service-directory": "^3.1.3",
     "eslint": "^7.0.0",
     "json-schema": "^0.3.0",
     "uuid": "^8.0.0"