Fix interactive code for one-field types (#176)

src/interactive.jl

@@ -17,7 +17,7 @@ Interactively create a plugin of type `T`. Implement this method and ignore othe
 related functions only if you want completely custom behaviour.
 """
 function interactive(T::Type)
-    pairs = interactive_pairs(T)
+    pairs = Vector{Pair{Symbol, Type}}(interactive_pairs(T))
 
     # There must be at least 2 MultiSelectMenu options.
     # If there are none, return immediately.

test/interactive.jl

@@ -198,6 +198,14 @@ end
             @test PT.interactive(TagBot) == TagBot(; changelog=nothing)
         end
 
+        @testset "Only one field" begin
+            print(
+                stdin.buffer,
+                DOWN, CR, DONE,  # Select "None" option
+            )
+            @test PT.interactive(Codecov) == Codecov()
+        end
+
         println()
     end
 end