Update multidict from 4.7.5 to 4.7.6 (#1474)
Update multidict from 4.7.5 to 4.7.6 (#1474)

Co-authored-by: Fábio Rosado <504d498c4e6912c88badf931727242f17b94f32f@gmail.com>
FabioRosado/opsdroid,jacobtomlinson/opsdroid,opsdroid/opsdroid