Use default configuration for code formatting with black

[maxrjones]

What is your issue?

As pointed out in #100 (comment), xbatcher currently uses a non-standard Black configuration with influences the configuration choices for other tools. I propose we switch to the default configuration now, given that the library is still small and only one release has been made.

This is the diff for changing to the default configuration:

xbatcher max$ git diff --stat
 .pre-commit-config.yaml               |   1 -
 asv_bench/benchmarks/benchmarks.py    |  54 +++++++++++++++-----------------
 doc/conf.py                           | 106 ++++++++++++++++++++++++++++++-------------------------------
 setup.py                              |   2 +-
 xbatcher/__init__.py                  |   2 +-
 xbatcher/accessors.py                 |  10 +++---
 xbatcher/generators.py                |  32 +++++++++----------
 xbatcher/loaders/torch.py             |  10 +++---
 xbatcher/tests/test_accessors.py      |  40 +++++++++++------------
 xbatcher/tests/test_generators.py     | 148 ++++++++++++++++++++++++++++++++++++++++----------------------------------------------
 xbatcher/tests/test_keras_loaders.py  |  26 +++++++--------
 xbatcher/tests/test_print_versions.py |   2 +-
 xbatcher/tests/test_torch_loaders.py  |  48 +++++++++++++---------------
 xbatcher/util/print_versions.py       |  38 +++++++++++-----------
 14 files changed, 246 insertions(+), 273 deletions(-)

Almost all of this is due to the removal of --skip-string-normalization, which is described in the docs as for If you are adopting Black in a large project with pre-existing string conventions. IMO xbatcher would be better off using defaults since it's not yet a large project.