Fix deprecation comments

Author: gustaphe

Project.toml

@@ -10,7 +10,7 @@ Unitful = "1986cc42-f94f-5a68-af5c-568840ba703d"
 [compat]
 RecipesBase = "1.0"
 Unitful = "0.16, 0.17, 0.18, 1.0"
-julia = "1.0 - 1.8.1"
+julia = "1.0"
 
 [extras]
 Plots = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"

src/UnitfulRecipes.jl

@@ -1,20 +1,22 @@
 module UnitfulRecipes
 
-@warn """
-UnitfulRecipes has been deprecated.
-
-```
-using Unitful, Plots
-```
-should suffice to plot unitful data.
-"""
-
 using RecipesBase
 using Unitful: Quantity, unit, ustrip, Unitful, dimension, Units
 export @P_str
 
 const clims_types = (:contour, :contourf, :heatmap, :surface)
 
+function __init__()
+    @warn """
+    UnitfulRecipes has been deprecated.
+
+    ```
+    using Unitful, Plots
+    ```
+    should suffice to plot unitful data.
+    """
+end
+
 #==========
 Main recipe
 ==========#