Log Message:
openexr: update to 3.1.3.

## Version 3.1.3 (October 27, 2021)

Patch release with a change to default zip compression level:

* Default zip compression level is now 4 (instead of 6), which in our
  tests improves compression times by 2x with only a tiny drop in
  compression ratio.
* ``setDefaultZipCompression()`` and ``setDefaultDwaCompression()``
  now set default compression levels for writing.
* The Header how has ``zipCompressionLevel()`` and
  ``dwaCompressionLevel()`` to return the levels used for writing.

Also, various bug fixes, build improvements, and documentation
updates. In particular:

* Fixes a build failure with Imath prior to v3.1
* Fixes a bug in detecting invalid chromaticity values

## Version 3.1.2 (October 4, 2021)

Patch release with various bug fixes, build improvements, and
documentation updates. In particular:

* Fix a test failure on arm7
* Proper handling of pthread with glibc 2.34+
* Miscellaneous fixes for handling of invalid input by the new
  OpenEXRCore library

With this version, the OpenEXR technical documentation formerly
distributed exclusivly as pdf's is now published online at
https://openexr.readthedocs.io, with the document source now
maintained as .rst files in the repo's docs subfolder.