Added missing using statement

src/ImageSharp/Processing/Processors/Effects/OilPaintingProcessor{TPixel}.cs

@@ -73,8 +73,8 @@ namespace SixLabors.ImageSharp.Processing.Processors.Effects
                             ref Vector4 vectorSpanRef = ref MemoryMarshal.GetReference(vectorSpan);
 
                             // Rent the shared buffer only once per parallel item
-                            IMemoryOwner<float> bins = configuration.MemoryAllocator.Allocate<float>(levels * 4);
+                            using (IMemoryOwner<float> bins = configuration.MemoryAllocator.Allocate<float>(levels * 4))
-
+                            {
                                 ref float binsRef = ref bins.GetReference();
                                 ref int intensityBinRef = ref Unsafe.As<float, int>(ref binsRef);
                                 ref float redBinRef = ref Unsafe.Add(ref binsRef, levels);
@@ -141,6 +141,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Effects
 
                                     PixelOperations<TPixel>.Instance.FromVector4Destructive(configuration, vectorSpan, targetRowSpan);
                                 }
+                            }
                         });
 
                 Buffer2D<TPixel>.SwapOrCopyContent(source.PixelBuffer, targetPixels);