Generalize exception type (#227)

In preparation for JuliaLang/julia#41885

Author: timholy

test/test_array.jl

@@ -171,7 +171,7 @@ const AG = ArchGDAL;
             nbands = 0,
             dtype = UInt8,
         ) do dataset
-            @test_throws ArgumentError AG.RasterDataset(dataset)
+            @test_throws Union{ArgumentError,MethodError} AG.RasterDataset(dataset)
             @test_throws DimensionMismatch AG._common_size(dataset)
         end
     end