Bugfixes

• spy: ensure bytes in write()

Bugfixes (posix)

• [#540] serialposix: Fix inconsistent state after exception in open()

Bugfixes (win32)

• [#530] win32: Fix exception for composite serial number search on Windows

Bugfixes (MacOS)

• [#542] list_ports_osx: kIOMasterPortDefault no longer exported on Big Sur
• [#545, #545] list_ports_osx: getting USB info on BigSur/AppleSilicon