Fix build

src/ImageSharp/Formats/Png/PngDecoderCore.cs

@@ -1261,7 +1261,7 @@ namespace SixLabors.ImageSharp.Formats.Png
 
             this.crc.Reset();
             this.crc.Update(this.chunkTypeBuffer);
-            this.crc.Update(chunk.Data.Array, 0, chunk.Length);
+            this.crc.Update(new ReadOnlySpan<byte>(chunk.Data.Array, 0, chunk.Length));
 
             if (this.crc.Value != chunk.Crc && IsCriticalChunk(chunk))
             {

src/ImageSharp/Formats/Png/PngEncoderCore.cs

@@ -659,7 +659,7 @@ namespace SixLabors.ImageSharp.Formats.Png
 
             BinaryPrimitives.WriteUInt32BigEndian(this.intBuffer, (uint)this.crc.Value);
 
-            stream.Write(intBuffer, 0, 4); // write the crc
+            stream.Write(this.intBuffer, 0, 4); // write the crc
         }
     }
 }