Bump async from 2.6.1 to 2.6.4

Bumps [async](https://github.com/caolan/async) from 2.6.1 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/v2.6.1...v2.6.4)

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

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

package-lock.json

@@ -152,11 +152,11 @@
       "dev": true
     },
     "async": {
-      "version": "2.6.1",
-      "resolved": "https://registry.npmjs.org/async/-/async-2.6.1.tgz",
-      "integrity": "sha512-fNEiL2+AZt6AlAw/29Cr0UDe4sRAHCpEHh54WMz+Bb7QfNcFw4h3loofyJpLeQs4Yx7yuqu/2dLgM5hKOs6HlQ==",
+      "version": "2.6.4",
+      "resolved": "https://registry.npmjs.org/async/-/async-2.6.4.tgz",
+      "integrity": "sha512-mzo5dfJYwAn29PeiJ0zvwTo04zj8HDJj0Mn8TD7sno7q12prdbnasKJHhkm2c1LgrhlJ0teaea8860oxi51mGA==",
       "requires": {
-        "lodash": "^4.17.10"
+        "lodash": "^4.17.14"
       }
     },
     "asynckit": {