Update animation to 3.0 API

Changed the property in the animation from "rotation_deg" to
"rotation_degrees."

2d/kinematic_character/colworld.tscn

@@ -105,7 +105,7 @@ length = 20.0
 loop = true
 step = 0.1
 tracks/0/type = "value"
-tracks/0/path = NodePath(".:rotation_deg")
+tracks/0/path = NodePath(".:rotation_degrees")
 tracks/0/interp = 1
 tracks/0/loop_wrap = true
 tracks/0/imported = false