Add support for v5.x.x of the AWS provider

The module has been updated to work with version 5.x.x of the AWS provider.

fix: Make aws_elasticache_parameter_group to use redis6.x as value fo…

…r family when version is 6 and above (terraform-community-modules#54)

multiaz enable add (terraform-community-modules#48)

Terraform 0.15.* updates (terraform-community-modules#50)

docs: Fixed README

docs: Fixed README

docs: Updated README

fix: add redis_version keeper for random_id.salt (terraform-community…

…-modules#41)

docs: Updated README

Fixing and preparing update for Terraform 0.12