Files opened by ParquetFileWriter’s appendFile method should to be closed correctly

I try to use the `appendFile` method of `ParquetFileWriter` to merge some smaller Parquet files into one large parquet file. After I finished the merge, I tried deleting the smaller files, but couldn't actually delete them.

After reading the ParquetFileWriter source code, I found that the file he opened was not closed in the end method, which seemed unreasonable.

When testing on `Windows`, it was found that these implicitly opened files cannot be deleted or renamed. This seems to be related to Windows file handles. But it's worked fine on macOS.

Anyway, I will submit a patch to ensure that files opened through the appendFile function are closed correctly.