Log Message:
py-fakefs: updated to 3.7.1

Version 3.7.1:
This version adds support for Python 3.7.6 and 3.8.1.

Fixes
* Adapted fake `pathlib` to changes in Python 3.7.6/3.8.1

Version 3.7:

Fixes
This version adds support for Python 3.8.

_Note:_ This is the last pyfakefs version that will support Python 2.7
and Python 3.4 (possible bug fix releases notwithstanding).

* added support for Python 3.8
* added preliminary support for Windows-specific `os.stat_result` attributes
  `tst_file_attributes` and `st_reparse_tag`
* added support for fake `os.sendfile` (Posix only, Python 3 only)

Fixes
* support `devnull` in Windows under Python 3.8
* fixed side effect of calling `DirEntry.stat()` under Windows (changed
  st_nlink)
* fixed problem of fake modules still referenced after a test in modules
  loaded during the test
* correctly handle missing read permission for parent directory
* raise for `os.scandir` with non-existing directory

Infrastructure
* fixed CI tests scripts to always propagate errors