GeographicLib 2.1.2 (released 2022-12-13)

Changes between 2.1.2 (released 2022-12-13) and 2.1.1 versions:

• Add MGRS::Decode to break an MGRS string into its components.

• Add definite integral overload for DST::integral. This is used in
  GeodesicExact.

• Add example code examples/AuxLatitude.[hc]pp implementating the
  AuxAngle and AuxLatitude classes. These classes implement the
  methods documented in the paper "On auxiliary latitudes",
  https://arxiv.org/abs/2212.05818. They are not part of
  GeographicLib. See Auxiliary latitudes for more details.

• Minor cmake issues:

  • fix cross-compile build on Windows;
  • check cmake version for "cmake rm -rf";
  • move cmake_minimum_required to the beginning of the cmake file
    and update minimum version to 3.13.0.