MNT: Use policy_max in cmake_minimum_required

[matthewfeickert]

• Set policy_max which defines the maximum CMake policy. cmake_minimum_required sets two minimums: the real (lower) minimum and the (upper) minimum based on has been tested with. The defaults (CMake policies) will be set to the highest value possible between the two values.
  • c.f. https://cmake.org/cmake/help/latest/command/cmake_minimum_required.html

Relevant for:

• Please build double-down as a aseparate package conda-forge/dagmc-feedstock#37
• Feature request: conda distribution #31
• Add double-down conda-forge/staged-recipes#32181

---

Example Pixi manifest that will build the project using the state of this PR:

[workspace]
channels = ["conda-forge"]
name = "double-down"
platforms = ["linux-64", "osx-arm64"]
version = "0.1.0"

[tasks.build]
cmd = """
rm -rf ./build && \
cmake $CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX -S . -B build && \
cmake build -LH && \
cmake --build build --clean-first --parallel "$(nproc -- ignore=2)" && \
ctest --test-dir build --output-on-failure && \
cmake --install build
"""

[dependencies]
cxx-compiler = ">=1.11.0,<2"
cmake = ">=4.2.3,<5"
make = ">=4.4.1,<5"
moab = ">=5.6.0,<6"
embree = ">=4.4.0,<5"
eigen = ">=3.4.0,<4"

$ pixi run build

[matthewfeickert]

👋 @pshriwise this is ready for review. Let me know if you have any questions.

[pshriwise]

This looks good! Thank you for the update @matthewfeickert 👍🏻

[matthewfeickert]

Thanks for the fast review and merge, @pshriwise. Can I also have you look at conda-forge/staged-recipes#32181 (which motivated this PR)?