imath: update to 3.1.10.

## Version 3.1.10 (January 26, 2024)

Patch release with various build/bug fixes.

Build fixes:

  - Fix a problem where downstream projects using Imath would build
    python bindings even if they weren't requested.
  - Fix for missing `std::bit_cast`
  - Fix missing/necessary use of IMATH_HOSTDEVICE
  - IMATH_INSTALL_PKG_CONFIG is now on by default, even on Windows
  - Fix calling default constructor by uniform init in TypeTraits
  - Fix redundant PYIMATH_EXPORTS causing compile issues on Windows Clang
  - Update to SO versioning policy:

    This change adopts a policy of appending the ``MAJOR.MINOR.PATCH``
    software release name to the ``SONAME`` to form the real name of the
    shared library.

    See [website/install.rst](website/install.rst) and [PR
    #339](https://github.com/AcademySoftwareFoundation/openexr/pull/339)
    for more details.

Bug fixes:

  - Fix half to float giving wrong results on older x86_64 CPUs on Windows

Other changes:

  - succ()/pred() now use std::nextafter().
  - Expand epsilon bounds for m44x pyImath test.
  - Rename "docs" to "website".
  - Add missing copyright/license identifiers.

### Merged Pull Requests

* \[[#363](https://github.com/AcademySoftwareFoundation/Imath/pull/363)\]
Update install instructions to reflect new SO versioning policy

* \[[#362](https://github.com/AcademySoftwareFoundation/Imath/pull/362)\]
Require sphinx 5.0

* \[[#361](https://github.com/AcademySoftwareFoundation/Imath/pull/361)\]
src/python/config/ModuleDefine.cmake: do not install a cmake file exporting targets for dependent projects

* \[[#358](https://github.com/AcademySoftwareFoundation/Imath/pull/358)\]
Fix half to float giving wrong results on older x86_64 CPUs on Windows

* \[[#353](https://github.com/AcademySoftwareFoundation/Imath/pull/353)\]
Changed implementation of succ and pred to use std::nextafter.

* \[[#350](https://github.com/AcademySoftwareFoundation/Imath/pull/350)\]
Fix check for the availability of std::bit_cast

* \[[#349](https://github.com/AcademySoftwareFoundation/Imath/pull/349)\]
IMATH_INSTALL_PKG_CONFIG is on by default, even on Windows

* \[[#347](https://github.com/AcademySoftwareFoundation/Imath/pull/347)\]
Export Imath from the build tree and so on.

* \[[#344](https://github.com/AcademySoftwareFoundation/Imath/pull/344)\]
rm unnecessary IMATH_HOSTDEVICE attributes.

* \[[#342](https://github.com/AcademySoftwareFoundation/Imath/pull/342)\]
Add missing copyright/license identifiers

* \[[#341](https://github.com/AcademySoftwareFoundation/Imath/pull/341)\]
Remove unnecessary files

* \[[#340](https://github.com/AcademySoftwareFoundation/Imath/pull/340)\]
Fix calling default constructor by uniform init.

* \[[#339](https://github.com/AcademySoftwareFoundation/Imath/pull/339)\]
Update and simply SO versioning policy

* \[[#338](https://github.com/AcademySoftwareFoundation/Imath/pull/338)\]
Rename "docs" to "website"

* \[[#333](https://github.com/AcademySoftwareFoundation/Imath/pull/333)\]
Expand epsilon bounds for m44x pyImath test

* \[[#331](https://github.com/AcademySoftwareFoundation/Imath/pull/331)\]
Fixed redundant PYIMATH_EXPORTS causing compile issues on Windows Clang

* \[[#326](https://github.com/AcademySoftwareFoundation/Imath/pull/326)\]
Use security@openexr.com for consistency

* \[[#320](https://github.com/AcademySoftwareFoundation/Imath/pull/320)\]
Add missing IMATH_HOSTDEVICE to Matrix33<T>::invert(bool)


(wiz)