Swiftgalaxy

Update colibre example ahead of tutorial.

Fixed a bug in iteration with SWIFTGalaxies that could cause particles from incorrect regions in snapshots to be read in some cases.

**Full Changelog**: https://github.com/SWIFTSIM/swiftgalaxy/compare/v1.2.0...v1.2.1

What's Changed
* Efficient iteration over SWIFTGalaxy objects by kyleaoman in https://github.com/SWIFTSIM/swiftgalaxy/pull/14


**Full Changelog**: https://github.com/SWIFTSIM/swiftgalaxy/compare/v1.1.0...v1.2.0

What's Changed
* Support SOAP halo catalogues by kyleaoman in https://github.com/SWIFTSIM/swiftgalaxy/pull/12
* Update dependencies by kyleaoman in https://github.com/SWIFTSIM/swiftgalaxy/pull/20


**Full Changelog**: https://github.com/SWIFTSIM/swiftgalaxy/compare/v1.0.5...v1.1.0

Adds support for using swiftgalaxy without a halo catalogue, e.g. to select particles within some spatial region and/or boolean mask and then make use of the rest of the swiftgalaxy features (spherical/cylindrical coordinates, masking, consistent coordinate frame, etc.). Also adds a cookbook example to the documentation for selecting all particles within a spherical aperture, with or without a halo catalogue.

Completes support for caesar halo catalogues now that caesar outputs the spatial extent of groups in the catalogue (so that we can use this to define a spatial mask for swiftsimio). Older caesar outputs are still compatible, but will inefficiently read the entire simulation volume (a warning will be issued at runtime in this case).