chore(deps): update dependency @slack/webhook to v7

Author: renovate[bot]

package.json

@@ -10,7 +10,7 @@
   },
   "devDependencies": {
     "@antfu/ni": "0.23.2",
-    "@slack/webhook": "6.1.0",
+    "@slack/webhook": "7.0.4",
     "@types/node": "18.19.79",
     "ts-node": "10.9.2",
     "typescript": "5.8.2"