Decode

What's Changed
* Fix minimum requirement of matplotlib by astropenguin in https://github.com/deshima-dev/decode/pull/56


**Full Changelog**: https://github.com/deshima-dev/decode/compare/v0.7.0...v0.7.1

New Contributors
* dependabot made their first contribution in https://github.com/deshima-dev/decode/pull/41

**Full Changelog**: https://github.com/deshima-dev/decode/compare/v0.6.1...v0.7.0

**Full Changelog**: https://github.com/deshima-dev/decode/compare/v0.6.0...v0.6.1

New Contributors
* Hoshock made their first contribution in https://github.com/deshima-dev/decode/pull/20

**Full Changelog**: https://github.com/deshima-dev/decode/compare/v0.5.9...v0.6.0

This release closes 15.

- Fix wrong version of pyyaml (`^3.13` → `^5.3`) in `pyproject.toml`
- Also update `poetry.lock`
- Update version numbers (0.5.8 → 0.5.9) written in:
- `pyproject.toml`
- `decode/__init__.py`
- `docs/conf.py`
- `tests/test_metadata.py`

This release closes 13.

- Update Python requirements (>=3.6.1 → >= 3.6)
- Also update poetry.lock
- Update version numbers (0.5.7 → 0.5.8) written in:
- pyproject.toml
- decode/__init__.py
- docs/conf.py
- tests/test_metadata.py