Current minizinc depends on Gecode 6.3, but last release is 6.2.0
https://github.com/MiniZinc/libminizinc/blob/a56602765b4294b796c063664733b28f5a663af7/CMakeLists.txt#L36
find_package(Gecode 6.3 COMPONENTS Driver Float Int Kernel Minimodel Search Set Support)
Current minizinc depends on Gecode 6.3, but last release is 6.2.0
https://github.com/MiniZinc/libminizinc/blob/a56602765b4294b796c063664733b28f5a663af7/CMakeLists.txt#L36