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](caolan/async@v2.6.3...v2.6.4)

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

Signed-off-by: dependabot[bot] <[email protected]>

yarn.lock

@@ -2006,9 +2006,9 @@ async-limiter@~1.0.0:
   integrity sha1-3TeelPDbgxCwgpH51kwyCXZmF/0=
 
 async@^2.6.2:
-  version "2.6.3"
-  resolved "https://registry.nlark.com/async/download/async-2.6.3.tgz?cache=0&other_urls=https%3A%2F%2Fregistry.nlark.com%2Fasync%2Fdownload%2Fasync-2.6.3.tgz#d72625e2344a3656e3a3ad4fa749fa83299d82ff"
-  integrity sha1-1yYl4jRKNlbjo61Pp0n6gymdgv8=
+  version "2.6.4"
+  resolved "https://registry.yarnpkg.com/async/-/async-2.6.4.tgz#706b7ff6084664cd7eae713f6f965433b5504221"
+  integrity sha512-mzo5dfJYwAn29PeiJ0zvwTo04zj8HDJj0Mn8TD7sno7q12prdbnasKJHhkm2c1LgrhlJ0teaea8860oxi51mGA==
   dependencies:
     lodash "^4.17.14"
 
@@ -8873,10 +8873,8 @@ watchpack@^1.7.4:
   resolved "https://registry.nlark.com/watchpack/download/watchpack-1.7.5.tgz#1267e6c55e0b9b5be44c2023aed5437a2c26c453"
   integrity sha1-EmfmxV4Lm1vkTCAjrtVDeiwmxFM=
   dependencies:
-    chokidar "^3.4.1"
     graceful-fs "^4.1.2"
     neo-async "^2.5.0"
-    watchpack-chokidar2 "^2.0.1"
   optionalDependencies:
     chokidar "^3.4.1"
     watchpack-chokidar2 "^2.0.1"