bring lighthouse-lambda up to node 12 and lighthouse 5.6

[AlanSwenson]

Since 8.10 is no longer available on AWS, this update brings the project up to Node10/12 as well lighthouse version 5.6. Also updates vulnerable npm packages. the main things that are happening is swapping serverless for chrome-aws-lambda and using await. I have updated the test as well, but probably needs further testing. Also still needs Readme updates. If you intend to merge this I will write that as well.

[baocancode]

Hi @AlanSwenson , thanks for all your efforts. Unfortunately, we do not actively maintain this project at the moment. Feel free to fork it to another repository with your changes.