chore: update clippy lints (#272)

* chore: fix clippy lints
---------

Co-authored-by: Luis Moreno <morenol@users.noreply.github.com>

src/tree/decision_tree_regressor.rs

@@ -767,7 +767,7 @@ mod tests {
             assert!((y_hat[i] - y[i]).abs() < 0.1);
         }
 
-        let expected_y = vec![
+        let expected_y = [
             87.3, 87.3, 87.3, 87.3, 98.9, 98.9, 98.9, 98.9, 98.9, 107.9, 107.9, 107.9, 114.85,
             114.85, 114.85, 114.85,
         ];
@@ -788,7 +788,7 @@ mod tests {
             assert!((y_hat[i] - expected_y[i]).abs() < 0.1);
         }
 
-        let expected_y = vec![
+        let expected_y = [
             83.0, 88.35, 88.35, 89.5, 97.15, 97.15, 99.5, 99.5, 101.2, 104.6, 109.6, 109.6, 113.4,
             113.4, 116.30, 116.30,
         ];