Upgrade to Rails 7.2

[tungleduyxyz]

Upgrade the engine to Rails 7.2.

• Require rails ~> 7.2 in the gemspec
• Require Ruby >= 3.1.0 (minimum Ruby version for Rails 7.2)

See killbill/killbill-admin-ui#655 for the corresponding kaui engine upgrade.

JRuby CI fix (i18n / Fiber.current)

CI on jruby-9.4.2.0 failed during boot with:

NoMethodError: undefined method `current' for Fiber:Class
Did you mean?  __current__
  initialize at i18n-1.15.2/lib/i18n/config.rb:14

Root cause: i18n 1.15.x switched I18n.config to fiber-based storage. The original 1.15.0 report (ruby-i18n/i18n#735) covered the Fiber[:i18n_config] call breaking CRuby < 3.2; 1.15.1/1.15.2 reworked that but I18n::Config#initialize still calls Fiber.current. JRuby 9.4.2.0 doesn't expose a public Fiber.current (only the internal __current__; the public alias was added in a later 9.4.x release), so any i18n >= 1.15.0 fails at boot on that runtime.

This PR therefore also:

• Locks i18n to ~> 1.14.0 (1.14.x has no fiber code path, and satisfies activesupport 7.2's i18n >= 1.6, < 2) — matching the existing pins in kaui and kaui-standalone
• Bumps CI JRuby from 9.4.2.0 to 9.4.15.0 (which provides a proper Fiber.current) — matching kaui's CI

[Copilot]

Pull request overview

Upgrades the killbill-deposit UI engine to Rails 7.2 and aligns runtime/CI constraints (Ruby/JRuby and i18n) to avoid JRuby boot failures caused by i18n’s fiber-based config storage.

Changes:

• Pin i18n to ~> 1.14.0 in the bundler resolution.
• Update gem runtime requirements to Rails ~> 7.2 and Ruby >= 3.1.0.
• Bump CI JRuby from 9.4.2.0 to 9.4.15.0.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
Gemfile	Adds an i18n pin to avoid i18n 1.15.x fiber-related incompatibilities on affected runtimes.
deposit.gemspec	Updates runtime requirements (Ruby minimum + Rails 7.2 dependency).
.github/workflows/ci.yml	Updates the JRuby version used in CI matrix runs.

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