fix compile error

wgpu-types/src/lib.rs

@@ -990,7 +990,7 @@ impl Features {
     /// Vertex formats allowed for creating and building BLASes
     #[must_use]
     pub fn allowed_vertex_formats_for_blas(&self) -> Vec<VertexFormat> {
-        let formats = Vec::new();
+        let mut formats = Vec::new();
         if self.contains(Self::RAY_TRACING_ACCELERATION_STRUCTURE) {
             formats.push(VertexFormat::Float32x3);
         }