remove workaround for StaticArrays API breakage now that they have fixed it (#343)

Author: jrevels

REQUIRE

@@ -1,5 +1,5 @@
 julia 0.7-rc3
-StaticArrays 0.5.0
+StaticArrays 0.8.3
 DiffResults 0.0.1
 DiffRules 0.0.4
 NaNMath 0.2.2

test/JacobianTest.jl

@@ -94,7 +94,6 @@ cfgx = ForwardDiff.JacobianConfig(sin, x)
 @test_throws ForwardDiff.InvalidTagException ForwardDiff.jacobian(f, x, cfgx)
 @test ForwardDiff.jacobian(f, x, cfgx, Val{false}()) == ForwardDiff.jacobian(f,x)
 
-
 ########################
 # test vs. Calculus.jl #
 ########################
@@ -173,7 +172,6 @@ cfg = ForwardDiff.JacobianConfig(nothing, x)
 scfg = ForwardDiff.JacobianConfig(nothing, sx)
 
 _diff(A) = diff(A; dims=1)
-_diff(A::StaticArray) = diff(A) # StaticArray's don't use dims kwarg (yet)
 
 actual = ForwardDiff.jacobian(_diff, x)
 @test ForwardDiff.jacobian(_diff, sx) == actual