fix rrule

Author: CarloLucibello

src/upsample.jl

@@ -213,7 +213,7 @@ end
 function ChainRulesCore.rrule(::typeof(upsample_bilinear), x; size)
     Ω = upsample_bilinear(x; size=size)
     function upsample_bilinear_pullback(Δ)
-        (NO_FIELDS, ∇upsample_bilinear(Δ; size=(Base.size(x,1),Base.size(x,2))), DoesNotExist())
+        (NO_FIELDS, ∇upsample_bilinear(Δ; size=(Base.size(x,1),Base.size(x,2))))
     end
     return Ω, upsample_bilinear_pullback
 end