feat: support Ruby 3.3 (lower minimum from 3.4 to 3.3)

[Copilot]

Ruby 3.3 remains under security maintenance until mid-2027. Requiring 3.4 as the minimum unnecessarily breaks consumers on supported Ruby versions.

Changes

• All gemspecs — required_ruby_version lowered from >= 3.4 to >= 3.3 across all 8 gems (providers + otel hook)
• CI matrix — Ruby "3.3" added to the test matrix for every job in .github/workflows/ruby.yml

• Fixes [FEATURE] Support all actively maintained Ruby versions #167

[josecolella]

@copilot Fix failing CI checks

[Copilot]

@copilot Fix failing CI checks

Fixed in 9f2f768. The failures were caused by openfeature-sdk 0.6.x (used by openfeature-meta_provider and openfeature-otel-hook) having required_ruby_version >= 3.4 — so Ruby 3.3 can't install it.

The fix:

• Removed Ruby 3.3 from the test_meta_provider and test_otel_hook CI jobs, and kept their gemspecs at >= 3.4 (genuinely required by the upstream SDK)
• The other 6 providers/hooks (which use openfeature-sdk 0.3.x / 0.4.x) support Ruby 3.3 fine and keep it in their CI matrix