Features
- feat: implement `sum`, `count`, and `count_nonzero` reductions [347][]
Maintenance
- chore: remove Python `3.7` support [355][]
- chore: use trusted publisher deployment [354][]
- chore: replace custom definition of np.isclose with numba's np.isclose [348][]
[355]: https://github.com/scikit-hep/vector/pull/355
[354]: https://github.com/scikit-hep/vector/pull/354
[347]: https://github.com/scikit-hep/vector/pull/347
[348]: https://github.com/scikit-hep/vector/pull/348