Remove unnecessary volatile modifier

Author: rameel

src/Ramstack.FileSystem.Amazon/S3UploadStream.cs

@@ -22,7 +22,7 @@ internal sealed class S3UploadStream : Stream
     private readonly FileStream _stream;
     private readonly List<PartETag> _partETags;
 
-    private volatile int _disposed;
+    private int _disposed;
 
     /// <inheritdoc />
     public override bool CanRead => false;