Showerpipe

What's Changed
* Enabled PythiaGenerator to work without a LHE file by jacanchaplais in https://github.com/jacanchaplais/showerpipe/pull/20


**Full Changelog**: https://github.com/jacanchaplais/showerpipe/compare/0.3.0...0.3.1

What's Changed
* Improved COO graph construction algorithm 16 by jacanchaplais in https://github.com/jacanchaplais/showerpipe/pull/17
* updated GHA build job to run on ubuntu-latest by jacanchaplais in https://github.com/jacanchaplais/showerpipe/pull/18
* Breaking change: fields in edge structured array renamed from "in" / "out" to "src" / "dst"


**Full Changelog**: https://github.com/jacanchaplais/showerpipe/compare/0.2.7...0.3.0

What's Changed
* Created a testing suite
* Updated the `repeated_hadronize()` function to return an empty generator when hadronisation not possible
* Removed `collections` members introduced after python 3.8
* badges to README by jacanchaplais in https://github.com/jacanchaplais/showerpipe/pull/13
* Added testing, updated repeated_hadronize(), and ensured python 3.8 compliance by jacanchaplais in https://github.com/jacanchaplais/showerpipe/pull/14

**Full Changelog**: https://github.com/jacanchaplais/showerpipe/compare/0.2.6...0.2.7

Automatic documentation fixed by exporting modules from init.

No changes to API. (Apologies for the frequency of minor patches, CI/CD should be done, now!)

Change log:
- patched incorrect implementation of `LheData.from_path()`, and renamed to `LheData.from_source()`
- improved type annotations
- improved memory efficiency of loading LHE data accessed via URLs

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- Added `config` attribute to `PythiaGenerator`, which gives Pythia settings flags as a dict of dicts
- Improved reprs for `PythiaEvent` and `PythiaGenerator`, displaying XML path, and showing config settings as a tree
- Ensured fixed order output for fields in structured arrays
- Added `repeat_hadronize()` function to `generator` module, to enable re-hadronising the same hard process and shower
- Improved error descriptiveness, type annotation coverage, and online documentation (with CI / CD workflow)

No known breaking changes.