Bump terser from 4.6.6 to 4.8.1

Bumps [terser](https://github.com/terser/terser) from 4.6.6 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

@@ -528,7 +528,7 @@
         },
         "util": {
           "version": "0.10.3",
-          "resolved": "http://registry.npmjs.org/util/-/util-0.10.3.tgz",
+          "resolved": "https://registry.npmjs.org/util/-/util-0.10.3.tgz",
           "integrity": "sha1-evsa/lCAUkZInj23/g7TeTNqwPk=",
           "dev": true,
           "requires": {
@@ -607,7 +607,7 @@
         },
         "chalk": {
           "version": "1.1.3",
-          "resolved": "http://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
+          "resolved": "https://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
           "integrity": "sha1-qBFcVeSnAv5NFQq9OHKCKn4J/Jg=",
           "dev": true,
           "requires": {
@@ -3634,7 +3634,7 @@
     },
     "json5": {
       "version": "0.5.1",
-      "resolved": "http://registry.npmjs.org/json5/-/json5-0.5.1.tgz",
+      "resolved": "https://registry.npmjs.org/json5/-/json5-0.5.1.tgz",
       "integrity": "sha1-Hq3nrMASA0rYTiOWdn6tn6VJWCE=",
       "dev": true
     },
@@ -5565,9 +5565,9 @@
       "dev": true
     },
     "terser": {
-      "version": "4.6.6",
-      "resolved": "https://registry.npmjs.org/terser/-/terser-4.6.6.tgz",
-      "integrity": "sha512-4lYPyeNmstjIIESr/ysHg2vUPRGf2tzF9z2yYwnowXVuVzLEamPN1Gfrz7f8I9uEPuHcbFlW4PLIAsJoxXyJ1g==",
+      "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",