Bump terser from 4.2.0 to 4.8.1

Bumps [terser](https://github.com/terser/terser) from 4.2.0 to 4.8.1.
- [Release notes](https://github.com/terser/terser/releases)
- [Changelog](https://github.com/terser/terser/blob/master/CHANGELOG.md)
- [Commits](https://github.com/terser/terser/commits)

---
updated-dependencies:
- dependency-name: terser
  dependency-type: indirect
...

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

package-lock.json

@@ -324,9 +324,9 @@
       }
     },
     "terser": {
-      "version": "4.2.0",
-      "resolved": "https://registry.npmjs.org/terser/-/terser-4.2.0.tgz",
-      "integrity": "sha512-6lPt7lZdZ/13icQJp8XasFOwZjFJkxFFIb/N1fhYEQNoNI3Ilo3KABZ9OocZvZoB39r6SiIk/0+v/bt8nZoSeA==",
+      "version": "4.8.1",
+      "resolved": "https://registry.npmjs.org/terser/-/terser-4.8.1.tgz",
+      "integrity": "sha512-4GnLC0x667eJG0ewJTa6z/yXrbLGv80D9Ru6HIpCQmO+Q4PfEtBFi0ObSckqwL6VyQv/7ENJieXHo2ANmdQwgw==",
       "dev": true,
       "requires": {
         "commander": "^2.20.0",