Feature/pre commit (#40)

* git pre-commit

* general update

* update version

* fix desc

Co-authored-by: Giulio Calzolari <giuliocalzolari@users.noreply.github.com>

minor update TF Code and Readme

add regexp support (#33)

* add regexp support

update terraform readme

fix debug message using format

update-python36 (#23)

Added suffix variable (#19)

[Resolve #12] cleanup old code

Fix index name parsed incorrectly if index format contains hyphen (#18)

If index format contains hyphen such as `index-2018-08-11`, the index date
is parsed as `index-2018-08` rather than `index`.

VPC support for the Lambda function (#10)

* Lambda function compatible with AWS ES VPC

When your Elasticsearch is running inside your VPC, you also need to run your Lambda function inside your VPC. 

Features:
* Create Security Group for Lambda
* Extend IAM role to allow VPC execution
* Add the variables subnet_ids 
* Add docs for lambda VPC support
* add tags and prefix to lambda
* clean-up python function
* add compatibility for public/vpc