[R] Provide backward compatibility for bridge to older versions of pyarrow

[asfimport]

After ARROW-15169 is merged, the Python--R bridge code will properly use external pointers to pass references to C API structures. The changes made on the R side will (probably) only work with the new pyarrow version. If it doesn't, it's not hard to provide backward compatibility:

pa <- reticulate::import("pyarrow")
if (package_version(pa$`__version__`) >= "6.0.0.9000") {
  # the new code
} else {
  # the old code
}
#> NULL

Reporter: Dewey Dunnington / @paleolimbot
Assignee: Dewey Dunnington / @paleolimbot

PRs and other links:

• GitHub Pull Request #12062

_{Note: This issue was originally created as ARROW-15173. Please see the migration documentation for further details.}

[asfimport]

Jonathan Keane / @jonkeane:
Issue resolved by pull request 12062
#12062