v0.21.0

fix: update s3 bucket & context tags @tirumerla (#62)

what

• Bump the tag for s3 bucket module to use >= 2.0 for aws provider to avoid module version conflicts when used with >= 3.0 modules (eg. aws-eks-node-group).
• Bump the tag to 0.21.0 for terraform-null-label module to support future versions of TF.

why

• This module is being used with terraform-aws-eks-node-group which needs aws provider version to be >= 2.0 to fix version conflicts.

references

• See cloudposse/terraform-aws-eks-node-group#41 for details. This tackles one of the modules causing the issue.