v2.0.1

> #### Updates

The fine timestamping feature has been fully validated with this release.

> #### Changes

* HAL: Adjusted the freq_offset field of received packets, to take into account
the channel IF resolution error.
* HAL: Refined the fine timestamp offset compared to Gateway v2, by taking into
account the frequency offset of the received packet.
* HAL: Fixed the preamble length for FSK downlinks
* MCU: Removed the binary compiled in debug mode.
* util_spectral_scan: actually use the nb_scan input argument which was ignored.