Log Message:
geography/gama: Update to 1.21

Changes in release 2.21

  - bugfixes

Changes in release 2.20 (2022-06-30)

  - The new algorithm ICGS (iterated classical Gram-Schmidt) in the
    class AdjGSO replaced the former algorithm MGS (modified
    Gram-Schmidt), which was implemented with column pivoting as a
    template class GSO. The template class GSO is meant only as a tool
    for testing purposes. Both initial scaling and pivoting with
    euclidean norms are not suitable for practical computations.

    The old legacy code with MGS used in the AdjGSO class is still
    available with conditional compilation directive statements if the
    name GNU_GAMA_GSO_LEGACY_CODE is defined.