chore(openfeature): pin mixpanel-ruby ~> 3.3 for fallback_reason (SDK-126)

[tylerjroach]

Bundler will refuse to resolve mixpanel-ruby ~> 3.3 until that version exists on RubyGems. That failure is the point of this PR — it enforces the correct two-step release sequencing.

Summary

• Bump openfeature-provider/mixpanel-ruby-openfeature.gemspec runtime dep: ~> 3.1 → ~> 3.3.
• Bump mixpanel-ruby-openfeature version: 0.1.0 → 0.2.0.
• Add openfeature/v0.2.0 CHANGELOG entry.

Why

The wrapper's openfeature-provider/lib/mixpanel/openfeature/provider.rb:81 dispatches on SelectedVariant#fallback_reason, which was introduced by the SDK-79 merge in #153. Both published mixpanel-ruby versions in the previous ~> 3.1 range — 3.1.0 and 3.2.0 — predate SDK-79 and lack fallback_reason. Any install that paired mixpanel-ruby-openfeature 0.1.0 with those would raise NoMethodError on every evaluation past the existing rescue StandardError block. Greptile caught this on #153 immediately post-merge.

Release sequencing

1. This PR (now): red on CI because mixpanel-ruby ~> 3.3 isn't published.
2. Release mixpanel-ruby 3.3.0 with the SDK-79 changes:
   • Bump lib/mixpanel-ruby/version.rb → 3.3.0 on master
   • Cut the RubyGems release via the existing release-rubygems.yml workflow
3. This PR flips green → merge + cut mixpanel-ruby-openfeature 0.2.0.

Verified locally

bundle install in openfeature-provider/:

Could not find compatible versions
Because mixpanel-ruby >= 3.3, < 4.A could not be found in source at `..`
and every version of mixpanel-ruby-openfeature depends on mixpanel-ruby ~> 3.3,
  mixpanel-ruby-openfeature cannot be used.

Exactly the error CI should produce.

Linear: SDK-126

[linear-code]

SDK-126

[greptile-apps]

Confidence Score: 5/5

This looks safe to merge.

• The dependency constraint matches the provider API requirement.
• The previously reported release-notes change is no longer present.
• No blocking issues remain in the changed code.

Important Files Changed

Filename	Overview
openfeature-provider/mixpanel-ruby-openfeature.gemspec	Raises the runtime dependency from mixpanel-ruby ~> 3.1 to ~> 3.3.

_{Reviews (4): Last reviewed commit: "Drop rationale comment above mixpanel-ru..." | Re-trigger Greptile}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.16%. Comparing base (3c54747) to head (8c9c8c9).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #166   +/-   ##
=======================================
  Coverage   97.16%   97.16%           
=======================================
  Files          15       15           
  Lines         775      775           
=======================================
  Hits          753      753           
  Misses         22       22           

Flag	Coverage Δ
openfeature	100.00% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.