Aiida-pseudo

Features
- Add support for Python 3.9 [[21]](https://github.com/aiidateam/aiida-pseudo/pull/21)
- `RecommendedCutoffMixin`: add concept of stringency levels [[20]](https://github.com/aiidateam/aiida-pseudo/pull/20)
- `UpfData`: automatically parse the Z valence from the file [[24]](https://github.com/aiidateam/aiida-pseudo/pull/24)

Fixes
- `PseudoPotentialFamily.get_pseudos`: maintain structure kind names [[20]](https://github.com/aiidateam/aiida-pseudo/pull/20)

Changes
- `PseudoPotentialFamily.get_pseudos`: turn arguments into keyword only [[7]](https://github.com/aiidateam/aiida-pseudo/pull/7)

Features
- Add support for the PSF format through the `PsfData` data plugin [[`2156b45f`]](https://github.com/aiidateam/aiida-pseudo/commit/2156b45f2adc6c0c1b11fe6e6a0c123df464c0af)
- Add support for the PSML format through the `PsmlData` data plugin [[`2156b45f`]](https://github.com/aiidateam/aiida-pseudo/commit/2156b45f2adc6c0c1b11fe6e6a0c123df464c0af)
- Add support for the PSP8 format through the `Psp8Data` [[11]](https://github.com/aiidateam/aiida-pseudo/pull/11)
- Add the `PsfFamily` group plugin for PSF pseudo potential families [[`2156b45f`]](https://github.com/aiidateam/aiida-pseudo/commit/2156b45f2adc6c0c1b11fe6e6a0c123df464c0af)
- Add the `PsmlFamily` group plugin for PSML pseudo potential families [[`2156b45f`]](https://github.com/aiidateam/aiida-pseudo/commit/2156b45f2adc6c0c1b11fe6e6a0c123df464c0af)
- Add the `Psp8Family` group plugin for PSP8 pseudo potential families [[11]](https://github.com/aiidateam/aiida-pseudo/pull/11)
- `PseudoPotentialFamily`: deduplicate existing pseudos [[5]](https://github.com/aiidateam/aiida-pseudo/pull/5)

Fixes
- `PseudoPotentialData`: maintain correct signature for `store` method

Devops
- Pre-commit: move `pylint` conf to `pyproject.toml` [[`2156b45f`]](https://github.com/aiidateam/aiida-pseudo/commit/2156b45f2adc6c0c1b11fe6e6a0c123df464c0af)
- Pre-commit: replace old format string interpolation with f-strings [[`302fb105`]](https://github.com/aiidateam/aiida-pseudo/commit/302fb1056489e2d1e1e59bf5011ea28388e8b6f2)

First release of `aiida-pseudo`.