setStaticPosition does not set Fixed mode

[PaulZC]

As observed by @adamgarbo - thanks!

In v2 of the library, setStaticPosition sets the mode to fixed:

https://github.com/sparkfun/SparkFun_u-blox_GNSS_Arduino_Library/blob/3416a3140fb74c3b80fc680140d029182fcd03ad/src/SparkFun_u-blox_GNSS_Arduino_Library.cpp#L7597

In v3, we've missed that step. In should happen here:

SparkFun_u-blox_GNSS_v3/src/u-blox_GNSS.cpp

Lines 7288 to 7289 in 3444ad3

	bool result = newCfgValset(layer);
	result &= addCfgValset8(UBLOX_CFG_TMODE_POS_TYPE, (uint8_t)latLong);