Update dependency @actions/core to v1.2.6 [SECURITY]

Author: renovate-bot

package-lock.json

@@ -25,7 +25,7 @@
   "author": "YourNameOrOrganization",
   "license": "MIT",
   "dependencies": {
-    "@actions/core": "1.2.4",
+    "@actions/core": "1.2.6",
     "@actions/github": "4.0.0",
     "@octokit/webhooks": "7.8.1",
     "git-blame-json": "1.0.1",