Secretbox

What's Changed
* [pre-commit.ci] pre-commit autoupdate by pre-commit-ci in https://github.com/Preocts/secretbox/pull/19
* Add codecov step into workflow by Preocts in https://github.com/Preocts/secretbox/pull/20
* [pre-commit.ci] pre-commit autoupdate by pre-commit-ci in https://github.com/Preocts/secretbox/pull/21
* Refactor to loader modules by Preocts in https://github.com/Preocts/secretbox/pull/22
* Tests refactor by Preocts in https://github.com/Preocts/secretbox/pull/26
* Create `load_from()` method by Preocts in https://github.com/Preocts/secretbox/pull/28


**Full Changelog**: https://github.com/Preocts/secretbox/compare/v1.5.0...v1.6.1

Added
`debug_flag` as a parameter when creating a SecretBox object. When present the class-level logger will be flipped to `DEBUG` level instead of the defaulted `ERROR`

Changes
- API Change: argument rename `aws_region` -> `aws_region_name` for consistency
- Performance: AWS client will not be created if boto3 is installed but `aws_region_name` or `aws_sstore_name` are empty/None
- Updated example in readme to use `auto_load=true`

Adds
- argument `aws_region_name` will be populated with environ variable `AWS_REGION_NAME` if exists. If provided, keyword argument will be used over any existing environ values.
- argument `aws_sstore_name` will be populated with environ variable `AWS_SSTORE_NAME` if exists. If provided, keyword argument will be used over any existing environ values.