Fix example SBP message in SBP Specification

[dgburr]

The example message shown in Chapter 4 of the SBP Specification is incorrect - the message ID for MSG_BASELINE_ECEF is 523 = 20Bh, not 514 = 202h.

[dgburr]

Test code in case you want to double-check my checksum calculation:

import sbp.navigation
import binascii

msg = sbp.navigation.MsgBaselineECEF(sender=1228, tow=416300400, x=-4145, y=-5905, z=6384, accuracy=0, n_sats=5, flags=0)
b = binascii.hexlify(msg.to_binary())
pairs = [str(b[i:i+2]) for i in range(0, len(b), 2)]
print('\n'.join(pairs))

[denniszollo]

LGTM. I'm surprised we didn't catch this after deprecating MSG_POS_ECEF during SBP 2.0 revamp. Thanks so much for catching and fixing!

[dgburr]

LGTM. I'm surprised we didn't catch this after deprecating MSG_POS_ECEF during SBP 2.0 revamp. Thanks so much for catching and fixing!

I didn't catch it - the problem was actually reported by a customer