Update cmake minimum version to 3.5

On a recent Ubuntu Linux 24.04.2, cmake no longer supports 2.6.0 configs (which is a minimum requirement in SWORD's CMakeLists.txt file), and the configuration step fails:

CMake Error at CMakeLists.txt:20 (CMAKE_MINIMUM_REQUIRED):
  Compatibility with CMake < 3.5 has been removed from CMake.

Update the VERSION argument <min> value. Or, use the <min>...<max> syntax to tell CMake that the project requires at least <min> but has been updated to work with policies introduced by <max> or earlier.

Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway.

In fact, the error can be worked around with the option expained above, but we should update the CMaleLists.txt file to require cmake version 3.5 (or above).