Pyubx2

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

What's Changed

ENHANCEMENTS:

1. Add SEC-OSNMA payload definition.

FIXES:

1. Fix SEC-SIGLOG payload definition - thanks to Niederb for contribution.
1. Cater for alternate (v1, v2) versions of SEC-SIG message = Fixes [156](https://github.com/semuconsulting/pyubx2/issues/156).


* Rc 1.2.45 by semuadmin in https://github.com/semuconsulting/pyubx2/pull/158
* Fix structure of `SEC-SIGLOG` by Niederb in https://github.com/semuconsulting/pyubx2/pull/157

New Contributors
* Niederb made their first contribution in https://github.com/semuconsulting/pyubx2/pull/157

**Full Changelog**: https://github.com/semuconsulting/pyubx2/compare/v1.2.44...v1.2.45