Fix: #2 by supporting both `nrfx v1.7.2` and `nrfx v2.1.0`
Nordic made significant breaking API changes to the RNG API
somewhere between nrfx v1.7.2 (which v1.0.0 of this library
was written for) and nrfx v2.1.0. These breaking API changes
were not listed in the nrfx changelog.
By sheer luck, a new macro was also defined with this version
bump, allowing this library to support either version of
the nrfx headers, with zero code change by library users.
Thanks to user @BitLox for reporting this issue, and his help testing the fix.
First release. Works with nRF52 series chips when using Adafruit Arduino BSP.