Fixing instructions in developers README on how to run pytest

[JavalVyas2000]

Fixing typo

Fixes the flag for running a single notebook which should have been -c instead of -v in the developer readme.

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📚 Documentation preview 📚: https://idaes-examples--90.org.readthedocs.build/en/90/

[JavalVyas2000]

I get the following error when I run the above command with -v flag.

ERROR: usage: pytest [options] [file_or_dir] [file_or_dir] [...]
pytest: error: unrecognized arguments: --nbmake --nbmake-timeout=600 -n idaes_examples/notebooks/docs/unit_models/operations/compressor_test.ipynb
  inifile: C:\Users\javal\Desktop\Internship\IDAES-examples\idaes_examples\pytest.ini
  rootdir: C:\Users\javal\Desktop\Internship\IDAES-examples\idaes_examples

[lbianchi-lbl]

From the dev call:

• pytest's behavior is affected by the working directory from which the pytest command is issued
• This is especially true for this repository, partially by design, since the working directory is responsible (together with the -c CLI flag) for determining which type of tests to run, i.e. either:
  • Testinge the build infrastructure
  • Testing the notebooks, i.e. running each _test.ipynb notebook with nbmake
• Because of this, we should make sure to always report the working directory alongside any output when discussing
• The current assessment is:
  • The instructions in main are wrong
  • However, this fix in this PR is also probably not fully addressing the issue
• Next steps:
  • @lbianchi-lbl to look into this to figure out what's the proper combination that doesn't result in errors

[ksbeattie]

Closing in preference to #106