installing with bower on heroku

I am working with heroku and flask. I am trying to use multibuild pack on heroku to build my dependencies. I came across this repo and followed the instructions.

First, I set my BUILDPACK_URL and checked it

=== corvid Config Vars
BUILDPACK_URL:               https://github.com/ddollar/heroku-buildpack-multi.git

.buildpacks file:

https://github.com/heroku/heroku-buildpack-nodejs
https://github.com/ejholmes/heroku-buildpack-bower
https://github.com/heroku/heroku-buildpack-python

My package.json looks as follows:

{
  "dependencies": {
    "bower": "latest"
  }
}

I deploy my project to heroku, but end up getting the following error whenever it tries to deploy.

=====> Downloading Buildpack: https://github.com/ejholmes/heroku-buildpack-bower
=====> Detected Framework: Bower buildpack

module.js:340
    throw err;
          ^
Error: Cannot find module 'bower-logger'
    at Function.Module._resolveFilename (module.js:338:15)
    at Function.Module._load (module.js:280:25)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at Object.<anonymous> (/tmp/build_4a6d8bfa-5458-4908-95bc-e6f3af6d5b2a/node_modules/bower/bin/bower:8:14)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)

 !     Push rejected, failed to compile Multipack app

What is the problem here?

Full project files can be found here