Added
- Informative error message for the env_var argument in the `redshift_execute()` and `redshift_get_conn()` functions
- A `boto_get_creds()` function was created to allow the user to obtain credentials strings for purposes such as `COPY` and `UNLOAD` SQL statements
- Version documentation in the `CHANGELOG.md` file
Changed
- The `create_session()` function was renamed to `boto_create_session()` to highlight that the session object can be used to access a wide variety of AWS tools