Xpart

**Changes:**
- Introduce retry for tests involving random number generation

**Full Changelog**: https://github.com/xsuite/xpart/compare/v0.9.1...v0.9.2

**Changes:**
- Fix issue with particle matching when R matrix is provided by the user

**Full Changelog**: https://github.com/xsuite/xpart/compare/v0.9.0...v0.9.1

**Changes:**
- Introduced "single-rf-harmonic" longitudinal matching engine. More efficient than the legacy one from PyHEADTAIL in matching distributions for very full buckets.
- Fixed issue with custom capacity in build_particles.
- Fixed issue with warnings in longitudinal matcher from PyHEADTAIL.

**Full Changelog**: https://github.com/xsuite/xpart/compare/v0.8.6...v0.9.0

**Changes:**
- Introduced Particle.pzeta property

**Full Changelog**: https://github.com/xsuite/xpart/compare/v0.8.5...v0.8.6

**Changes:**
- build_particles accepts nemitt_x and nemitt_y (scale_with_transverse_norm_emitt is deprecated).
- build_particles can match transverse distribution using the 4d twiss (usage: build_particles(..., method="4d", ...).
- Read-only check in Particles.energy.
- Version number accessible as xobjects.__version__.

**Full Changelog**: https://github.com/xsuite/xpart/compare/v0.8.4...v0.8.5

**Changes:**
- Handle local_particle_src in a way that is compatible with python multithreading