chore(deps): update dependency chai to v6

Author: renovate[bot]

package-lock.json

@@ -45,7 +45,7 @@
     "tz-parser": "3.1.3"
   },
   "devDependencies": {
-    "chai": "4.5.0",
+    "chai": "6.2.1",
     "eslint": "4.19.1",
     "eslint-config-standard": "11.0.0",
     "eslint-plugin-import": "2.25.4",