[PATCH] docs: Add release note for Django 1.8 to 1.10 removal

[Stephen Finucane]

On Mon, 2018-09-10 at 17:07 -0600, Stephen Finucane wrote:
> Signed-off-by: Stephen Finucane <stephen at that.guru>
> Fixes: e97bd5ca0 ("Remove support for Django 1.8, 1.9, 1.10")

Trivial fix. Applied.