cad/apio: Update 1.5.0 => 1.5.1

[alven]

Summary

• Clarify LICENSE [0] [0] https://github.com/FPGAwars/apio/issues/778
• Fix USE_PYTHON=concurrent when only one of Python 2 or 3 is supported AND not using flavors does not make any sense (by portlint(1))
• Replace custom shebang fixing with standard one

Test Plan

For every {151amd64, 144amd64}:

• Successful poudriere testport
• Successful run-testing