Shape-1 fields in NumPy dtypes deprecated

[lsigrist]

Recent NumPy 1.17.0 raises FutureWarning on import:

data.py:454: FutureWarning: Passing (type, 1) or '1type' as a synonym of type is deprecated;
in a future version of numpy, it will be understood as (type, (1,)) / '(1,)type'.

See also: https://docs.scipy.org/doc/numpy/release.html#shape-1-fields-in-dtypes-won-t-be-collapsed-to-scalars-in-a-future-version

Relates to: https://gitlab.ethz.ch/tec/public/rocketlogger/-/issues/129