To build:
$ make
Recommended to build on EC2 instance using amzn-ami-hvm-2016.03.3.x86_64-gp2 AMI, as lxml dependency includes source files that ultimately are linked into some ELF shared objects.
WEBHOOK_URL must be configured with the Slack Incoming Webhook URL.
- Makefile target for release (utilise AWS CLI to update Lambda function)
- Error handling