refactor: apply isort on wily codebase

[skarzi]

There is one action to do when this commit will be squashed to the main branch:

• add squashed commit with this PR to .git-blame-ignore-revs

[codecov-commenter]

Codecov Report

Merging #163 (a103c2a) into master (8353468) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #163   +/-   ##
=======================================
  Coverage   95.23%   95.23%           
=======================================
  Files          23       23           
  Lines        1216     1216           
  Branches      291      291           
=======================================
  Hits         1158     1158           
  Misses         33       33           
  Partials       25       25           

Impacted Files	Coverage Δ
src/wily/__init__.py	100.00% <100.00%> (ø)
src/wily/__main__.py	95.48% <100.00%> (ø)
src/wily/archivers/__init__.py	100.00% <100.00%> (ø)
src/wily/archivers/filesystem.py	100.00% <100.00%> (ø)
src/wily/archivers/git.py	87.50% <100.00%> (ø)
src/wily/cache.py	98.18% <100.00%> (ø)
src/wily/commands/build.py	89.01% <100.00%> (ø)
src/wily/commands/diff.py	88.75% <100.00%> (ø)
src/wily/commands/graph.py	100.00% <100.00%> (ø)
src/wily/commands/index.py	100.00% <100.00%> (ø)
... and 9 more

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[tonybaloney]

Thanks!