chore: release 5.5.0 (#418)

🤖 I have created a release \*beep\* \*boop\*
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## [5.5.0](https://www.github.com/googleapis/nodejs-security-center/compare/v5.4.1...v5.5.0) (2021-08-23)


### Features

* turns on self-signed JWT feature flag ([#417](https://www.github.com/googleapis/nodejs-security-center/issues/417)) ([ec4b179](https://www.github.com/googleapis/nodejs-security-center/commit/ec4b17916d42f9ff006b9c9d0c1a6c2dd0743fa7))
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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).

security-center/snippets/package.json

@@ -14,7 +14,7 @@
   "license": "Apache-2.0",
   "dependencies": {
     "@google-cloud/pubsub": "^2.0.0",
-    "@google-cloud/security-center": "^5.4.1"
+    "@google-cloud/security-center": "^5.5.0"
   },
   "devDependencies": {
     "chai": "^4.2.0",