Use separate Pylint steps in CI for hepdata_lib and tests directories

[GraemeWatt]

hepdata_lib/.github/workflows/tests.yml

Lines 144 to 148 in ba9f2e2

	- name: Run pylint
	if: ${{ always() && !startsWith(matrix.python-version, '3.6') && !startsWith(matrix.python-version, '3.7') }}
	run: |
	python -m pylint hepdata_lib/*.py
	python -m pylint tests/*.py

I noticed in PR #265 that the CI is successful for commit 81adb42 (workflow run) despite the command python -m pylint hepdata_lib/*.py giving a exit code 8 with a message:

************* Module hepdata_lib
hepdata_lib/__init__.py:237:4: R0912: Too many branches (13/12) (too-many-branches)

-----------------------------------
Your code has been rated at 9.99/10

Thus it looks like only the second command python -m pylint tests/*.py giving Your code has been rated at 10.00/10 (exit code 0) determines whether the "Run pylint" step passes or fails. The subsequent commit 51f13c1 (workflow run) gives issues for both the hepdata_lib and tests directories and the "Run pylint" step fails. This PR therefore separates the single "Run pylint" step into separate steps for the hepdata_lib and tests directories so that a code rating less than 10.00/10 (corresponding to a non-zero exit code for pylint) for either directory will result in the CI failing.

---

📚 Documentation preview 📚: https://hepdata-lib--267.org.readthedocs.build/en/267/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.37%. Comparing base (ba9f2e2) to head (e0c9d26).
Report is 8 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #267   +/-   ##
=======================================
  Coverage   90.37%   90.37%           
=======================================
  Files           5        5           
  Lines        1112     1112           
  Branches      251      251           
=======================================
  Hits         1005     1005           
  Misses         78       78           
  Partials       29       29           

Flag	Coverage Δ
unittests-3.10	90.37% <ø> (ø)
unittests-3.11	90.37% <ø> (ø)
unittests-3.6	90.09% <ø> (ø)
unittests-3.7	90.09% <ø> (ø)
unittests-3.8	90.19% <ø> (ø)
unittests-3.9	90.19% <ø> (ø)

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[clelange]

Thanks, good catch! I would have thought that the first failing command should have exited and have the workflow fail but apparently it doesn't...