Bump web-ext from 5.5.0 to 6.0.0

Bumps [web-ext](https://github.com/mozilla/web-ext) from 5.5.0 to 6.0.0.
- [Release notes](https://github.com/mozilla/web-ext/releases)
- [Commits](mozilla/web-ext@5.5.0...6.0.0)

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

package.json

@@ -88,7 +88,7 @@
     "ts-loader": "^8.0.17",
     "typescript": "^4.2.2",
     "typescript-plugin-css-modules": "^3.2.0",
-    "web-ext": "^5.5.0",
+    "web-ext": "^6.0.0",
     "webpack": "^4.41.6",
     "webpack-cli": "^4.5.0",
     "webpack-extension-reloader": "^1.1.4",