chore(main): release 6.3.0 (#502)

* chore(main): release 6.3.0

* 🦉 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]

security-center/snippets/package.json

@@ -14,7 +14,7 @@
   "license": "Apache-2.0",
   "dependencies": {
     "@google-cloud/pubsub": "^3.0.0",
-    "@google-cloud/security-center": "^6.2.0"
+    "@google-cloud/security-center": "^6.3.0"
   },
   "devDependencies": {
     "chai": "^4.2.0",