feat: Update citations for pylhe through 2022

Adds and updates the pylhe citations listed in https://github.com/scikit-hep/pylhe/issues/181 that are not already listed on the Scikit-HEP publication page.

Probing compressed higgsinos with forward protons at the LHC
- c.f. https://inspirehep.net/literature/2140007
MadMiner: Machine learning-based inference for particle physics
- c.f. https://inspirehep.net/literature/1746275
Benchmarking simplified template cross sections in WH production
- c.f. https://inspirehep.net/literature/1750323
Photon collider search strategy for sleptons and dark matter at the LHC
- c.f. https://inspirehep.net/literature/1703804

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