[Ruby] Deprecate Plasma Ruby bindings

[asfimport]

Reporter: Antoine Pitrou / @pitrou
Assignee: Kouhei Sutou / @kou

Related issues:

• [Python] Deprecate Plasma Python bindings (is a clone of)
• [Java] Deprecate Plasma JNI bindings (is cloned by)

PRs and other links:

• GitHub Pull Request #14258

_{Note: This issue was originally created as ARROW-17864. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
@kou

[asfimport]

Kouhei Sutou / @kou:
Issue resolved by pull request 14258
#14258