arrow

MINOR: [Dev] Add anjakefala and davisusanibar to the contributors list (#36357)

### Rationale for this change

Disclaimer: These are both colleagues of mine.

@ davisusanibar has been an Arrow Java maintainer for > 1 year.
@ anjakefala is taking a more active role in contributing to pyarrow issues/triaging, which has an incredibly high volume.

Authored-by: Dane Pitkin <dane@voltrondata.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>