xtb version 6.2.3

Semiempirical Extended Tight-Binding Program Package Maintenance and bugfix release. Thanks to Jan Unsleber for contributing to this release. Bugfix: JSON dump did not return correct version number Bugfix: Sign error in printout for GFN1-xTB Mulliken charges Bugfix: PDB charges were not written correctly in PDB output Bugfix: SRB strain derivatives were wrong Bugfix: EEQ returns correct energy for one atom systems The error handling has been completely reworked Improved implementation of CM5 charges Analytical gradients for the Halogen-bond correction Benzene is now available as synonym for toluene for GFN2/GBSA Massively improved C-API Gaussian external input and output formats CMake support for building xtb GCC support for building xtb with both meson and CMake This release is API compatible to version 6.2.