docs: tested/supported MCEGs and drop Python 3.8 support

[APN-Pucky]

Closes: #291

• udpate scikit-hep-testdata to 0.5.5
• Load the files from scikit-hep-testdata in tests, added in feat: add more MC lhe files for pylhe scikit-hep-testdata#180

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.86%. Comparing base (6f9d9fd) to head (d36fe17).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #298      +/-   ##
==========================================
+ Coverage   94.84%   94.86%   +0.01%     
==========================================
  Files           2        2              
  Lines         330      331       +1     
  Branches       69       61       -8     
==========================================
+ Hits          313      314       +1     
  Misses         10       10              
  Partials        7        7              

Flag	Coverage Δ
unittests-3.10	94.86% <100.00%> (+0.01%)	⬆️
unittests-3.11	94.86% <100.00%> (+0.01%)	⬆️
unittests-3.12	94.86% <100.00%> (+0.01%)	⬆️
unittests-3.13	94.86% <100.00%> (+0.01%)	⬆️
unittests-3.8	?
unittests-3.9	94.86% <100.00%> (+0.01%)	⬆️

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[Copilot]

Pull Request Overview

This PR updates the testing infrastructure to use the latest scikit-hep-testdata (0.5.5), expands LHE reader tests to cover additional generators, and adjusts documentation and CI to match the new Python requirement.

• Bump Python requirement to >=3.9 and scikit-hep-testdata to >=0.5.5
• Add test fixtures for MadGraph, Pythia, Sherpa, and Whizard LHE outputs
• Update README with supported generator versions and drop Python 3.8 from CI

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/test_lhe_reader.py	Added new TEST_FILES lists for various generators and broadened parametrized tests
src/pylhe/init.py	Changed Iterable import to collections.abc.Iterable
pyproject.toml	Require Python >=3.9, bump scikit-hep-testdata to >=0.5.5, remove 3.8 classifier
README.md	Documented tested Monte Carlo generators and their versions
.github/workflows/ci.yml	Removed Python 3.8 from CI matrix

Comments suppressed due to low confidence (2)

tests/test_lhe_reader.py:181

• [nitpick] The test function name test_read_lhe_with_attributes_powheg no longer matches its broadened scope. Rename it to something like test_read_lhe_with_attributes_generator to reflect that it covers all generators.

def test_read_lhe_with_attributes_powheg(file):

README.md:25

• The version 5-2.0.0 for MadGraph5 seems to include an extra 5- prefix. It should likely read 2.0.0 to match the actual tested version.

| [MadGraph5](https://launchpad.net/mg5amcnlo)   | 5-2.0.0, 2.2.1, 3.5.8 |

[APN-Pucky]

@all-contributors please add @APN-Pucky for documentation, maintenance.

[allcontributors]

@APN-Pucky

I've put up a pull request to add @APN-Pucky! 🎉

[eduardo-rodrigues]

Hi. This is really nice to see. Thank you!

Let's see if @matthewfeickert can also have a look but otherwise do not wait longer than today and merge.

[APN-Pucky]

Before I merge it I will remove the python3.8 check on the branch protection rule as required check.

[APN-Pucky]

... and add 3.13 as required.