Update dependency cron to v4

Author: renovate[bot]

package-lock.json

@@ -33,7 +33,7 @@
         "chartjs-node-canvas": "^4.1.6",
         "cheerio": "^1.0.0-rc.12",
         "closest-match": "1.3.3",
-        "cron": "^3.1.7",
+        "cron": "^4.0.0",
         "csv-parser": "3.0.0",
         "csv-writer": "1.6.0",
         "discord-api-types": "0.37.90",