Bump uglify-js from 3.9.2 to 3.9.3

Bumps [uglify-js](https://github.com/mishoo/UglifyJS) from 3.9.2 to 3.9.3.
- [Release notes](https://github.com/mishoo/UglifyJS/releases)
- [Commits](mishoo/UglifyJS@v3.9.2...v3.9.3)

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

package.json

@@ -24,7 +24,7 @@
     "istanbul": "0.4.5",
     "mocha": "7.1.2",
     "pad-right": "0.2.2",
-    "uglify-js": "3.9.2",
+    "uglify-js": "3.9.3",
     "brace-expansion": "1.1.11"
   },
   "comment": "brace-expansion is installed because an old insecure version is used by one of the dev depencencies (under istanbul)",