Bump Optim compat to include v2 (#136)

Optim.jl 2.0 was released with breaking changes around autodiff API,
but this package doesn't use the affected autodiff keyword argument,
so only the compat bound needs updating.

Author: baggepinnen

Project.toml

@@ -1,7 +1,7 @@
 name = "RobustAndOptimalControl"
 uuid = "21fd56a4-db03-40ee-82ee-a87907bee541"
 authors = ["Fredrik Bagge Carlson", "Marcus Greiff"]
-version = "0.4.46"
+version = "0.4.47"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
@@ -40,7 +40,7 @@ LinearMPC = "0.7"
 MatrixEquations = "2"
 MatrixPencils = "1"
 MonteCarloMeasurements = "1.0"
-Optim = "1.5"
+Optim = "1.5, 2"
 Plots = "1"
 RecipesBase = "1"
 SparseArrays = "1"