python3-scons: upgrade 4.8.0 -> 4.8.1

python3-scons: upgrade 4.8.0 -> 4.8.1

Changelog:
==========
- env.Dump() previously accepted a single optional "key" argument.
- SCons 4.8.0 added an __all__ specifier at the top of the Variables
  module (Variables/__init__.py) to control what is made available in
  a star import.
- Fix a problem with AppendUnique and PrependUnique where a value could
  be erroneously removed due to a substring match.
- Fix handling of ListVariable when supplying a quoted choice containing
  a space character
- On win32 platform, SCons 4.7.0 modified the determination
  of the output encoding of piped processes.
- Improve wording of manpage "Functions and Environment Methods" section.
- Make doc function signature style more consistent - tweaks to AddOption,
  DefaultEnvironment and Tool,.
- sctypes is_* functions given explicit return types.

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>