Bump web-ext from 5.3.0 to 5.4.0

Bumps [web-ext](https://github.com/mozilla/web-ext) from 5.3.0 to 5.4.0.
- [Release notes](https://github.com/mozilla/web-ext/releases)
- [Commits](https://github.com/mozilla/web-ext/compare/5.3.0...5.4.0)

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

package.json

@@ -53,7 +53,7 @@
     "typescript": "^3.9.7",
     "uglify-es": "^3.3.9",
     "uglifyjs-webpack-plugin": "^2.2.0",
-    "web-ext": "^5.3.0",
+    "web-ext": "^5.4.0",
     "web-ext-types": "^3.2.1",
     "webpack": "^4.44.2",
     "webpack-cli": "^3.3.12"