Bump async from 2.6.3 to 2.6.4

Bumps [async](https://github.com/caolan/async) from 2.6.3 to 2.6.4.
- [Release notes](https://github.com/caolan/async/releases)
- [Changelog](https://github.com/caolan/async/blob/v2.6.4/CHANGELOG.md)
- [Commits](https://github.com/caolan/async/compare/v2.6.3...v2.6.4)

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

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

package-lock.json

@@ -1802,9 +1802,9 @@
       "dev": true
     },
     "async": {
-      "version": "2.6.3",
-      "resolved": "https://registry.npmjs.org/async/-/async-2.6.3.tgz",
-      "integrity": "sha512-zflvls11DCy+dQWzTW2dzuilv8Z5X/pjfmZOWba6TNIVDm+2UDaJmXSOXlasHKfNBs8oo3M0aT50fDEWfKZjXg==",
+      "version": "2.6.4",
+      "resolved": "https://registry.npmjs.org/async/-/async-2.6.4.tgz",
+      "integrity": "sha512-mzo5dfJYwAn29PeiJ0zvwTo04zj8HDJj0Mn8TD7sno7q12prdbnasKJHhkm2c1LgrhlJ0teaea8860oxi51mGA==",
       "dev": true,
       "requires": {
         "lodash": "^4.17.14"
@@ -9688,9 +9688,9 @@
       }
     },
     "terser": {
-      "version": "4.8.1",
-      "resolved": "https://registry.npmjs.org/terser/-/terser-4.8.1.tgz",
-      "integrity": "sha512-4GnLC0x667eJG0ewJTa6z/yXrbLGv80D9Ru6HIpCQmO+Q4PfEtBFi0ObSckqwL6VyQv/7ENJieXHo2ANmdQwgw==",
+      "version": "4.6.11",
+      "resolved": "https://registry.npmjs.org/terser/-/terser-4.6.11.tgz",
+      "integrity": "sha512-76Ynm7OXUG5xhOpblhytE7X58oeNSmC8xnNhjWVo8CksHit0U0kO4hfNbPrrYwowLWFgM2n9L176VNx2QaHmtA==",
       "dev": true,
       "requires": {
         "commander": "^2.20.0",