Solo-epd-loader

<!-- Release notes generated using configuration in .github/release.yml at v0.4.2 -->

What's Changed
- Small bugfix concerning changes introduced with cdflib 1.3.3 (cf. [v0.4.0](https://github.com/jgieseler/solo-epd-loader/releases/tag/v0.4.0))
- Add support for Python 3.13

**Full Changelog**: https://github.com/jgieseler/solo-epd-loader/compare/v0.4.1...v0.4.2

<!-- Release notes generated using configuration in .github/release.yml at v0.4.1 -->

What's Changed
- Improve support for EPT level 3 data by providing more metadata
- Change package structure to follow new OpenAstronomy template (using pyproject.toml instead of setup.cfg)
- Drop support for Python 3.8

**Full Changelog**: https://github.com/jgieseler/solo-epd-loader/compare/v0.4.0...v0.4.1

<!-- Release notes generated using configuration in .github/release.yml at v0.4.0 -->

What's Changed
- **Add support for EPT level 3 data.** This dataset provides the electron data already in a corrected form. In addition, pitch angles with respect to the average magnetic field are provided. The dataset is structured a bit different, see [Example 5 in the README](https://github.com/jgieseler/solo-epd-loader?tab=readme-ov-file#example-5---ept-level-3-data). Not all data-manipulation functions support the new dataset yet (e.g., `combine_channels`).
- [cdflib fixed a very old bug in 1.3.3](https://github.com/MAVENSDC/cdflib/releases/tag/1.3.3). Unfortunately, that change is breaking the workaround used so far to bypass the bug. This update fixes the occurring problems while being backwards compatible to cdflib<1.3.3. This might lead to small problems in existing code that obtains channel energy information (e.g., use `meta['Electron_Bins_Text'][0]` instead of `meta['Electron_Bins_Text'][0][0]`).
- Verify compatibility with Python 3.11 and 3.12



**Full Changelog**: https://github.com/jgieseler/solo-epd-loader/compare/v0.3.8...v0.4.0

<!-- Release notes generated using configuration in .github/release.yml at v0.3.7 -->

What's Changed
- **Change default behavior:** With this version, the time index denotes the center of the measurement time interval (before it was the start). This behavior can be changed with the new ` pos_timestamp` option (defaults to `'center'`, alternatively use `'start'` for previous behavior).
- Add experimental function `combine_pixels` that averages (per time step and energy) the fluxes (and uncertainties) of a list of STEP pixels into a combined pixel.
- Implement custom warnings
- Internal & small code changes

**Full Changelog**: https://github.com/jgieseler/solo-epd-loader/compare/v0.3.6...v0.3.7

<!-- Release notes generated using configuration in .github/release.yml at v0.3.6 -->

What's Changed
- (Preliminary) Add new function `calc_ept_corrected_e` to correct EPT electron measurements for ion contamination

**Full Changelog**: https://github.com/jgieseler/solo-epd-loader/compare/v0.3.5...v0.3.6

<!-- Release notes generated using configuration in .github/release.yml at v0.3.5 -->

What's Changed
- Fix a bug occurring with cdflib<1.0

**Full Changelog**: https://github.com/jgieseler/solo-epd-loader/compare/v0.3.4...v0.3.5