mismatched Sponsor level item and title Platinum & Sapphire

[seokho-son]

https://github.com/openstack-kr/ocp-days-2023/blob/main/openinfradays/views.py#L79

def sponsors(request):
    diamond = Sponsor.objects.filter(level='Diamond')
    sapphire = Sponsor.objects.filter(level='Sapphire')

를 고려하면,

https://github.com/openstack-kr/ocp-days-2023/blob/main/templates/index.html#L94

            </div>
            <div class="row">
                {% for d in Platinum %}

를 수정해야 하지 않나 싶습니다. :)