message: cmake: don't use Python from framework
  No idea how this stuff works but it's worth a try to tame cmake on
  macOS.
diff: @@ -5,6 +5,7 @@ include(ExternalProject)
  # Without this GitHub actions picks the wrong python3 executable.
  set(Python3_FIND_REGISTRY "NEVER")
  +set(Python3_FIND_FRAMEWORK "NEVER")
  find_package(Python3 COMPONENTS Interpreter REQUIRED)
  if (NOT MAVLINK_DIALECT)
  