chore(deps): update dependency chai to v6

Author: renovate[bot]

package.json

@@ -38,7 +38,7 @@
     "xml-c14n": "^0.0.6"
   },
   "devDependencies": {
-    "chai": "4.5.0",
+    "chai": "6.0.0",
     "codeclimate-test-reporter": "0.5.1",
     "coveralls": "3.1.0",
     "eslint": "5.16.0",