cmake: fix build with cmake 4.0.0

[tgurr]

Fixes CMake >= 4.0.0 build failure:

CMake Error at CMakeLists.txt:1 (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.

[lgritz]

I believe this is fine as it stands.

Though the CI run reveals that, unrelated to this PR, our CI has rusted away a bit and is failing because the GHA runners themselves have broken things. We need to update the CI workflow, much like we did for other projects a couple months back, to do the trick to make the right npm still work with the old ASWF images (or just switch to newer images).

[LecrisUT]

  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.

This is actually the preferred approach, particularly use <max> with the highest version in the CI. This will reduce the downstream maintenance when the next round of deprecation hits in a couple of years.