chore(deps-dev): bump rollup-plugin-uglify from 6.0.3 to 6.0.4

Bumps [rollup-plugin-uglify](https://github.com/TrySound/rollup-plugin-uglify) from 6.0.3 to 6.0.4.
- [Release notes](https://github.com/TrySound/rollup-plugin-uglify/releases)
- [Commits](https://github.com/TrySound/rollup-plugin-uglify/compare/v6.0.3...v6.0.4)

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

package.json

@@ -45,7 +45,7 @@
     "rollup-plugin-serve": "^1.0.1",
     "rollup-plugin-terser": "^5.1.2",
     "rollup-plugin-typescript2": "^0.26.0",
-    "rollup-plugin-uglify": "^6.0.3",
+    "rollup-plugin-uglify": "^6.0.4",
     "rollup-plugin-visualizer": "^3.3.1",
     "start-server-and-test": "^1.10.11",
     "typescript": "^3.7.2",