Cmake error while installing Pygplates

Actually installing conda’s cmake worked for me. Prior to that (on Ubuntu 18.04, same as you) I got the following error. I think it’s because the version of the system cmake is only 3.10 whereas conda’s cmake is 3.21 (and so it’s builtin FindBoost script has more bug fixes).

CMake Error at /home/gplates/miniconda3/envs/pygplates_py38/lib/cmake/Boost-1.72.0/BoostConfig.cmake:120 (find_package):
  Could not find a package configuration file provided by "boost_python3"
  (requested version 1.72.0) with any of the following names:

    boost_python3Config.cmake
    boost_python3-config.cmake

  Add the installation prefix of "boost_python3" to CMAKE_PREFIX_PATH or set
  "boost_python3_DIR" to a directory containing one of the above files.  If
  "boost_python3" provides a separate development package or SDK, be sure it
  has been installed.
Call Stack (most recent call first):
  /home/gplates/miniconda3/envs/pygplates_py38/lib/cmake/Boost-1.72.0/BoostConfig.cmake:185 (boost_find_component)
  /usr/share/cmake-3.10/Modules/FindBoost.cmake:242 (find_package)
  src/CMakeLists.txt:221 (find_package)