Pyubx2

What's Changed
* update to 1.2.51 by semuadmin in https://github.com/semuconsulting/pyubx2/pull/179

1. Update minimum versions of pynmeagps (1.0.49) and pyrtcm (1.1.5) to ensure latest fixes and enhancements are included in NMEA and RTCM3 processing.
1. No other functional changes to UBX processing.

**Full Changelog**: https://github.com/semuconsulting/pyubx2/compare/v1.2.50...v1.2.51

FIXES:

1. Fix typos in AID-ALPSRV message definitions - thanks to wheirman for contribution.
1. Add alternate AID-ALPSRV Request and Send GET message types.

ENHANCEMENTS:

1. Minor internal streamlining of helper methods.

**Full Changelog**: https://github.com/semuconsulting/pyubx2/compare/v1.2.49...v1.2.50

What's Changed
* Rc 1.2.49 by semuadmin in https://github.com/semuconsulting/pyubx2/pull/174

1. Enhance val2bytes() helper method exception handling to explicitly state expected value type. e.g.

...
TypeError: Attribute type X001 value 0 must be <class 'bytes'>, not <class 'int'>


**Full Changelog**: https://github.com/semuconsulting/pyubx2/compare/v1.2.48...v1.2.49

What's Changed
* RC 1.2.48 by semuadmin in https://github.com/semuconsulting/pyubx2/pull/167

1. Add helper methods `val2twoscomp` and `val2signmag` to convert signed integer to appropriate two's complement or sign magnitude binary representation. Can be helpful when populating UBX ESF-MEAS `dataField` values such as speed or wheel tick, as these use both varieties of [signed integer representation](https://en.wikipedia.org/wiki/Signed_number_representations).

**Full Changelog**: https://github.com/semuconsulting/pyubx2/compare/v1.2.47...v1.2.48

What's Changed
* Rc 1.2.47 by semuadmin in https://github.com/semuconsulting/pyubx2/pull/160

1. Add 37 additional config database keys for F9P HPG 1.50 (FYI UBX NAV-TIMETRUSTED message type 0x0164 added in this firmware version, but definition not yet publicly documented).
1. Drop active support for Python 3.8, which is now End of Life.

**Full Changelog**: https://github.com/semuconsulting/pyubx2/compare/v1.2.46...v1.2.47

What's Changed
* update to v1.2.46 by semuadmin in https://github.com/semuconsulting/pyubx2/pull/159

1. Minimum version of pynmeagps updated to 1.0.42 - incorporates additional NMEA sentence definitions and helper functions.

**Full Changelog**: https://github.com/semuconsulting/pyubx2/compare/v1.2.45...v1.2.46