[+]Avian(Backend) - GravityScale::Default changed to 1.0f32 (#464)

# Objective

Fixes #463 

## Solution

Default implemented with 1.0

---------

Co-authored-by: Joona Aalto <[email protected]>

src/dynamics/rigid_body/mod.rs

@@ -430,14 +430,18 @@ pub(crate) struct PreSolveAngularVelocity(pub Vector);
 ///     ));
 /// }
 /// ```
-#[derive(
-    Component, Reflect, Debug, Clone, Copy, PartialEq, PartialOrd, Default, Deref, DerefMut, From,
-)]
+#[derive(Component, Reflect, Debug, Clone, Copy, PartialEq, PartialOrd, Deref, DerefMut, From)]
 #[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 #[cfg_attr(feature = "serialize", reflect(Serialize, Deserialize))]
 #[reflect(Debug, Component, Default, PartialEq)]
 pub struct GravityScale(pub Scalar);
 
+impl Default for GravityScale {
+    fn default() -> Self {
+        Self(1.0)
+    }
+}
+
 /// Determines how coefficients are combined for [`Restitution`] and [`Friction`].
 /// The default is `Average`.
 ///