graphics/openexr: security update to 3.1.4

• Several bug fixes to properly reject invalid input upon read
• Miscellaneous documentation improvements

This addresses one public security vulnerability:

• CVE-2021-45942 Heap-buffer-overflow in Imf_3_1::LineCompositeTask::execute

Changelog:
https://github.com/AcademySoftwareFoundation/openexr/blob/v3.1.4/CHANGES.md#version-314-january-26-2022

Security: CVE-2021-45942
MFH: 2022Q1
(cherry picked from commit c67fbf11b4bd1c8b3cbbf2abc99deadf4cec2892)