v0.20.0

readme updated, BridgeCrew compliance fixes @maximmi (#57)

what

• BridgeCrew compliance checks fix
• readme updated
• code clean up
• default behaviour changed: Instance Metadata Service Version 2 forced by default
• default behaviour changed: Encryption of the root block device enabled by default

why

• To be able to position our modules as standards compliant
• Providing explicit note about NAT instance with public IP
• removed unnecessary providers dependencies
• To comply BridgeCrew check
• To comply BridgeCrew check

references

• https://docs.bridgecrew.io/docs/public_12
• https://docs.bridgecrew.io/docs/general_13
• https://docs.bridgecrew.io/docs/bc_aws_general_31