[OpenZaak-discuss] Release 1.3.1

From the changelog https://github.com/open-zaak/open-zaak/blob/master/CHANGELOG.rst:

Changes

- Updated CMIS-adapter to 1.1 featuring support CMIS 1.0 Webservice binding and various new configuration options. - Added support for configurable Selectielijst years to retrieve specific years from the Selectielijst API (#689) - Prevent error monitoring from logging special personal data (#696)

Bugfixes

- Accept comma separated in EigenschapSpecificatie.waardenverzameling (#686)

Documentation

- Added SPDX license headers and check. - Added Docker storage hint to make sure users run the Docker containers on volumes with enough disk space.