Bump xml2js and web-ext

Bumps [xml2js](https://github.com/Leonidas-from-XIV/node-xml2js) to 0.5.0 and updates ancestor dependency [web-ext](https://github.com/mozilla/web-ext). These dependencies need to be updated together.


Updates `xml2js` from 0.4.23 to 0.5.0
- [Commits](https://github.com/Leonidas-from-XIV/node-xml2js/commits/0.5.0)

Updates `web-ext` from 7.5.0 to 7.6.2
- [Release notes](https://github.com/mozilla/web-ext/releases)
- [Commits](https://github.com/mozilla/web-ext/compare/7.5.0...7.6.2)

---
updated-dependencies:
- dependency-name: xml2js
  dependency-type: indirect
- dependency-name: web-ext
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -25,7 +25,7 @@
     "stylelint": "^13.5.0",
     "stylelint-config-standard": "^20.0.0",
     "stylelint-order": "^4.0.0",
-    "web-ext": "^7.5.0",
+    "web-ext": "^7.6.2",
     "webextensions-jsdom": "^1.2.1"
   },
   "homepage": "https://github.com/mozilla/multi-account-containers#readme",