Update dependency @octokit/webhooks to v7.6.4

Author: renovate-bot

package-lock.json

@@ -27,7 +27,7 @@
   "dependencies": {
     "@actions/core": "1.2.4",
     "@actions/github": "3.0.0",
-    "@octokit/webhooks": "7.5.0",
+    "@octokit/webhooks": "7.6.4",
     "git-blame-json": "1.0.1",
     "php-codesniffer": "1.0.2",
     "picomatch": "2.2.2"