[R] Use .arrow as extension of IPC files of datasets

[asfimport]

Related to ARROW-17072

As noted in the following document, the recommended extension for IPC files is now .arrow.

We recommend the “.arrow” extension for files created with this format.
https://arrow.apache.org/docs/format/Columnar.html#ipc-file-format

However, currently when writing a dataset with the write_dataset function, the default extension is .feather when feather is selected as the format, and .ipc when ipc is selected.

arrow/r/R/dataset-write.R

Lines 124 to 126 in f295da4

	format = c("parquet", "feather", "arrow", "ipc", "csv"),
	partitioning = dplyr::group_vars(dataset),
	basename_template = paste0("part-{i}.", as.character(format)),

Reporter: SHIMA Tatsuya / @eitsupi
Assignee: Kazuyuki Ura / @mopcup

Related issues:

• [Docs] Add note about "Feather" to the IPC file format document (relates to)
• [Python] Use .arrow as extension for IPC file dataset (is related to)

PRs and other links:

• GitHub Pull Request #13690

_{Note: This issue was originally created as ARROW-17088. Please see the migration documentation for further details.}

[asfimport]

Kazuyuki Ura / @mopcup:
I'll work on this.

[asfimport]

Neal Richardson / @nealrichardson:
Issue resolved by pull request 13690
#13690