build(deps): bump async from 2.6.1 to 3.1.0

Bumps [async](https://github.com/caolan/async) from 2.6.1 to 3.1.0.
- [Release notes](https://github.com/caolan/async/releases)
- [Changelog](https://github.com/caolan/async/blob/master/CHANGELOG.md)
- [Commits](caolan/async@v2.6.1...v3.1.0)

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

package.json

@@ -49,7 +49,7 @@
     "sinon": "^3.1.0"
   },
   "dependencies": {
-    "async": "^2.6.1",
+    "async": "^3.1.0",
     "bindings": "^1.3.0",
     "block-stream2": "^1.1.0",
     "colors": "^1.3.0",