Bump async to 2.6.4

This allows switching to more recent lodash, and fixes CVE.

Issue: S3UTILS-109

Author: francoisferrand

package.json

@@ -28,7 +28,7 @@
   "dependencies": {
     "JSONStream": "^1.3.5",
     "arsenal": "git+https://github.com/scality/arsenal#8.1.59",
-    "async": "^2.6.1",
+    "async": "^2.6.4",
     "aws-sdk": "^2.1005.0",
     "heapdump": "^0.3.15",
     "level": "^7",

yarn.lock

@@ -558,25 +558,25 @@ async-limiter@~1.0.0:
   resolved "https://registry.yarnpkg.com/async-limiter/-/async-limiter-1.0.0.tgz#78faed8c3d074ab81f22b4e985d79e8738f720f8"
   integrity sha512-jp/uFnooOiO+L211eZOoSyzpOITMXx1rBITauYykG3BRYPu8h0UcxsPNB04RR5vo4Tyz3+ay17tR6JVf9qzYWg==
 
-async@^2.1.4, async@^2.5.0, async@^2.6.1:
+async@^2.1.4, async@^2.5.0:
   version "2.6.1"
   resolved "https://registry.yarnpkg.com/async/-/async-2.6.1.tgz#b245a23ca71930044ec53fa46aa00a3e87c6a610"
   integrity sha512-fNEiL2+AZt6AlAw/29Cr0UDe4sRAHCpEHh54WMz+Bb7QfNcFw4h3loofyJpLeQs4Yx7yuqu/2dLgM5hKOs6HlQ==
   dependencies:
     lodash "^4.17.10"
 
-async@^3.2.0:
-  version "3.2.3"
-  resolved "https://registry.yarnpkg.com/async/-/async-3.2.3.tgz#ac53dafd3f4720ee9e8a160628f18ea91df196c9"
-  integrity sha512-spZRyzKL5l5BZQrr/6m/SqFdBN0q3OCI0f9rjfBzCMBIP4p75P620rR3gTmaksNOhmzgdxcaxdNfMy6anrbM0g==
-
-async@~2.6.4:
+async@^2.6.4, async@~2.6.4:
   version "2.6.4"
   resolved "https://registry.yarnpkg.com/async/-/async-2.6.4.tgz#706b7ff6084664cd7eae713f6f965433b5504221"
   integrity sha512-mzo5dfJYwAn29PeiJ0zvwTo04zj8HDJj0Mn8TD7sno7q12prdbnasKJHhkm2c1LgrhlJ0teaea8860oxi51mGA==
   dependencies:
     lodash "^4.17.14"
 
+async@^3.2.0:
+  version "3.2.3"
+  resolved "https://registry.yarnpkg.com/async/-/async-3.2.3.tgz#ac53dafd3f4720ee9e8a160628f18ea91df196c9"
+  integrity sha512-spZRyzKL5l5BZQrr/6m/SqFdBN0q3OCI0f9rjfBzCMBIP4p75P620rR3gTmaksNOhmzgdxcaxdNfMy6anrbM0g==
+
 asynckit@^0.4.0:
   version "0.4.0"
   resolved "https://registry.yarnpkg.com/asynckit/-/asynckit-0.4.0.tgz#c79ed97f7f34cb8f2ba1bc9790bcc366474b4b79"