Build(deps): Bump async from 2.6.2 to 2.6.4 in /src

Bumps [async](https://github.com/caolan/async) from 2.6.2 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@v2.6.2...v2.6.4)

---
updated-dependencies:
- dependency-name: async
  dependency-type: direct:production
...

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

Author: dependabot[bot]

src/package-lock.json

@@ -18,7 +18,7 @@
   "license": "ISC",
   "dependencies": {
     "@project-sunbird/telemetry-sdk": "0.0.9",
-    "async": "^2.4.0",
+    "async": "^2.6.4",
     "azure-storage": "2.7.0",
     "body-parser": "^1.14.2",
     "cassandra-driver": "^3.4.1",