py-distro: updated to 1.7.0

1.7.0 (2022.02.15)

BACKWARD COMPATIBILITY:
* Dropped support for EOL Pythons 2.7, 3.4 and 3.5
* Dropped support for LSB and `uname` back-ends when `--root-dir` is specified
* Moved `distro.py` to `src/distro/distro.py`

ENHANCEMENTS:
* Documented that `distro.version()` can return an empty string on rolling releases
* Documented support for Python 3.10
* Added official support for Rocky Linux distribution
* Added a shebang to `distro.py` to allow standalone execution
* Added support for AIX platforms
* Added compliance for PEP-561

BUG FIXES:
* Fixed `include_uname` parameter oversight
* Fixed crash when `uname -rs` output is empty
* Fixed Amazon Linux identifier in `distro.id()` documentation
* Fixed OpenSuse >= 15 support
* Fixed encoding issues when opening distro release files
* Fixed `linux_distribution` regression

(adam)