Add missing routes for sprites @2x

Author: frodrigo

api/app.py

@@ -133,6 +133,16 @@ def marker_gl_sprite_png():
     return Response(open("api/assets/marker-gl-sprite.png", "rb").read())
 
 
+@app.get("/0.3/assets/marker-gl-sprite@2x.json")
+def marker_gl_sprite_2x_json():
+    return Response(open("api/assets/marker-gl-sprite@2x.json", "rb").read())
+
+
+@app.get("/0.3/assets/marker-gl-sprite@2x.png")
+def marker_gl_sprite_2x_png():
+    return Response(open("api/assets/marker-gl-sprite@2x.png", "rb").read())
+
+
 @app.get("/0.3/assets/markers/{filename:path}.png")
 def marker(filename):
     file_path = f"api/markers/{filename}.png"