Bump async from 2.6.3 to 3.2.2

Bumps [async](https://github.com/caolan/async) from 2.6.3 to 3.2.2.
- [Release notes](https://github.com/caolan/async/releases)
- [Changelog](https://github.com/caolan/async/blob/master/CHANGELOG.md)
- [Commits](caolan/async@v2.6.3...v3.2.2)

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

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

package.json

@@ -33,7 +33,7 @@
   },
   "homepage": "https://github.com/noopkat/avrgirl-arduino",
   "dependencies": {
-    "async": "^2.6.3",
+    "async": "^3.2.2",
     "awty": "^0.1.0",
     "browser-serialport": "git+https://github.com/noopkat/browser-serialport.git#c8628c41c11890d3058875994c15f83f2df8185b",
     "chip.avr.avr109": "^1.1.1",