GH-49030: [Ruby] Add support for writing fixed size binary array

[kou]

Rationale for this change

It's a fixed size variant of binary array.

What changes are included in this PR?

• Add ArrowFormat::FixedSizeBinaryType#to_flatbuffers
• Add ArrowFormat::FixedSizeBinaryArray#each_buffer

Are these changes tested?

Yes.

Are there any user-facing changes?

Yes.

• GitHub Issue: [Ruby] Add support for writing fixed size binary array #49030

[github-actions]

⚠️ GitHub issue #49030 has been automatically assigned in GitHub to PR creator.

[hiroyuki-sato]

+1

LD_LIBRARY_PATH=/tmp/local/lib:/path/to/arrow/red-arrow/ext/arrow/ GI_TYPELIB_PATH=/tmp/local/lib/girepository-1.0 rake  test
cd /path/to/arrow/ruby/red-arrow-format
/path/to/.rbenv/versions/3.4.7/bin/ruby test/run.rb
Loaded suite test
Started
/path/to/arrow/ruby/red-arrow-format/lib/arrow-format/file-reader.rb:40: warning: IO::Buffer is experimental and both the Ruby and C interface may change in the future!
Finished in 1.662531537 seconds.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
142 tests, 142 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
85.41 tests/s, 85.41 assertions/s
cd -