---
fixes:
  - |
    On clouds where Keystone usernames are `case-insensitive
    <https://docs.openstack.org/keystone/latest/admin/case-insensitive.html>`_,
    Heat will now allow usernames with any case as property and
    parameter values where a Keystone user is expected
    (i.e. a ``keystone.user`` custom constraint applies).
    Previously the case had to match the case with which the name
    was stored in Keystone, even if Keystone itself was
    case-insensitive.