devel/py-futures: Update to 3.0.3

• Update to 3.0.3 [1]
• Add LICENSE_FILE
• Sort USE_PYTHON
• Add regression-test target for QA
• Update pkg-descr WWW: URL

Changes:

https://github.com/agronholm/pythonfutures/blob/3.0.3/CHANGES

Based on:

PR: 201068 [1]
Submitted by: Gasol Wu <gasol dot wu gmail com> [1]