Your first warning tells you that this feature was moved from a nn.Module approach to a nn.functional approach. The first one lets you instantiate layers as objects (modules), and then call them on some input later on, using their .forward() method. E.g:
interpolate = nn.Upsample(scale_factor=2, mode='nearest')
...
output = interpolate(input)

However, the nn.functional approach literally means that they are functions to be called directly! E.g:
output = nn.functional.interpolate(input, scale_factor=2, mode='nearest')

This means that you would not instantiate this kind of layer in the create_modules method of your darknet.