Upgrade to nodejs v12
This PR upgrades the sample project to support NodeJS v12 environment of AWS Lambda.
It now uses https://github.com/alixaxel/chrome-aws-lambda to manage the Chromium binary. chrome-aws-lambda goes to great effort to generate a binary for every version of Puppeteer. As a result, the version of puppeteer is no longer pinned to v1.3.0, but can now run the latest and greatest.
I have removed the locally managed binaries, as well as the option to download Chromium from S3. I personally don't use the S3 functionality, and if other people need it, I would steer them to the new Lambda Layers functionality. This project https://github.com/shelfio/chrome-aws-lambda-layer packages up the chrome-aws-lambda binary as an easy-to-use layer, if people are finding the size of the bundled Chromium binary in this starter-kit taking them over the 50mb Lambda package limit.