Bump matplotlib from 3.4.2 to 3.4.3

See merge request !298

Bump numpy from 1.20.3 to 1.21.2

See merge request !300

Bump pytest from 6.2.4 to 6.2.5

See merge request !302

Bump typing-extensions from 3.10.0.0 to 3.10.0.2

See merge request !304

Bumps [typing-extensions](https://github.com/python/typing) from 3.10.0.0 to 3.10.0.2.
- [Release notes](https://github.com/python/typing/releases)
- [Commits](https://github.com/python/typing/compare/3.10.0.0...3.10.0.2)

Bumps [pytest](https://github.com/pytest-dev/pytest) from 6.2.4 to 6.2.5.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/main/CHANGELOG.rst)
- [Commits](https://github.com/pytest-dev/pytest/compare/6.2.4...6.2.5)

Bumps [numpy](https://github.com/numpy/numpy) from 1.20.3 to 1.21.2.
- [Release notes](https://github.com/numpy/numpy/releases)
- [Changelog](https://github.com/numpy/numpy/blob/main/doc/HOWTO_RELEASE.rst.txt)
- [Commits](https://github.com/numpy/numpy/compare/v1.20.3...v1.21.2)

Bumps [matplotlib](https://github.com/matplotlib/matplotlib) from 3.4.2 to 3.4.3.
- [Release notes](https://github.com/matplotlib/matplotlib/releases)
- [Commits](https://github.com/matplotlib/matplotlib/compare/v3.4.2...v3.4.3)

remove History.mask to fix masking="none" issues

Closes #222

See merge request rdm-software/saqc!294

Remove the `nodata` parameter

See merge request !296

set flags at all (i.e. through early returns) or only UNTOUCHED
flags. This breaks the positional flagging scheme, which should
have one digit for every funtion applied.

likely flag the masked values

added a calibration plot to flag_pattern, because its hard to find a suitable threshold without any feedback.

rewrite of _restoreFlags() in register.py which was needed because of a problem updating meta, which raised an index error when setting meta on an empty history

Historymeta

See merge request !284

Expose data and flag through `SaQC`

See merge request !282