fix: package.json & yarn.lock to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-OCTOKITREQUESTERROR-8730854

package.json

@@ -18,7 +18,7 @@
     "@actions/core": "^1.2.6",
     "@actions/exec": "^1.0.4",
     "@actions/github": "^2.2.0",
-    "@octokit/core": "^3.5.1"
+    "@octokit/core": "^6.1.5"
   },
   "devDependencies": {
     "@types/jest": "^27.4.0",