pyupgrade @ 3.7

[tony]

https://github.com/asottile/pyupgrade

pip install pyupgrade autoflake; \
pyupgrade --py37 tests/**/*.py docs/**/*.py vcspull/**/*.py; \
poetry run autoflake tests/**/*.py docs/**/*.py vcspull/**/*.py -i --ignore-init-module-imports --exclude vcspull/_compat.py; \
make black isort

vcs-python/libvcs#305

[codecov]

Codecov Report

Merging #353 (712630e) into master (2eaf559) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #353      +/-   ##
==========================================
- Coverage   85.27%   85.25%   -0.03%     
==========================================
  Files          12       12              
  Lines         618      617       -1     
==========================================
- Hits          527      526       -1     
  Misses         91       91              

Impacted Files	Coverage Δ
vcspull/exc.py	100.00% <ø> (ø)
tests/helpers.py	81.48% <100.00%> (ø)
tests/test_sync.py	95.16% <100.00%> (ø)
vcspull/config.py	96.69% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 2eaf559...712630e. Read the comment docs.