Rebuild for spdlog 1.15

[regro-cf-autotick-bot]

This PR has been triggered in an effort to update spdlog115.

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[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/meta.yaml) and found it was in an excellent condition.

[traversaro]

@conda-forge-admin please rerender

[h-vetinari]

@conda-forge-admin, please rerender

[h-vetinari]

Seems we'd need to change the heyoka pin here (=in the upstream package, or patch it out)

CMake Error at CMakeLists.txt:177 (find_package):
  Could not find a configuration file for package "heyoka" that is compatible
  with requested version "6".

  The following configuration files were considered but not accepted:

    $PREFIX/lib/cmake/heyoka/heyoka-config.cmake, version: 7.3.0

[h-vetinari]

Seems we'd need to change the heyoka pin here

Seems that backporting just esa/cascade@b791b18 is not enough:

======================================================================
ERROR: test_kepler_equivalence (cascade.test.dynamics_test_case)
----------------------------------------------------------------------
TypeError: Unregistered type : heyoka::v35::expression

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/conda/feedstock_root/build_artifacts/cascade_1753273444580/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehol/lib/python3.10/site-packages/cascade/test.py", line 54, in test_kepler_equivalence
    dyn1 = simple_earth(
  File "/home/conda/feedstock_root/build_artifacts/cascade_1753273444580/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehol/lib/python3.10/site-packages/cascade/dynamics/_simple_earth.py", line 132, in simple_earth
    dyn = kepler(mu=GMe_SI)
TypeError: Unable to convert function return value to a Python type! The signature was
	(mu: float = 1.0) -> list[tuple[heyoka::v35::expression, heyoka::v35::expression]]