Fix compiling input setup file in nested folders

[peymanslh]

Closes #1312

Changelog-friendly one-liner: Fix compiling input setup.py file in nested folders

Contributor checklist

• Provided the tests for the changes.
• Gave a clear one-line description in the PR (that the maintainers can add to CHANGELOG.md on release).
• Assign the PR to an existing or new milestone for the target version (following Semantic Versioning).

[codecov]

Codecov Report

Merging #1324 (a92734a) into master (2be5cbf) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1324   +/-   ##
=======================================
  Coverage   99.62%   99.62%           
=======================================
  Files          33       33           
  Lines        2921     2928    +7     
  Branches      318      318           
=======================================
+ Hits         2910     2917    +7     
  Misses          5        5           
  Partials        6        6           

Impacted Files	Coverage Δ
piptools/scripts/compile.py	100.00% <100.00%> (ø)
tests/test_cli_compile.py	100.00% <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 2be5cbf...a92734a. Read the comment docs.

[atugushev]

@peymanslh thanks! Could you add a test for this particular case?

[atugushev]

Thanks for the test! A few comments below:

[atugushev]

Nice 👍🏼

[atugushev]

@AndydeCleyre it's okay if we merge this before #1329? What do you think?

[AndydeCleyre]

@AndydeCleyre it's okay if we merge this before #1329? What do you think?

Sure, I still need to add more tests, I'll rebase later and iron any wrinkles out.

[atugushev]

Wonderfull! Thanks, @peymanslh!

[peymanslh]

Wonderfull! Thanks, @peymanslh!

Thanks for your review and suggestion!