Don't allocate an empty hash for each call to #eligible?

[elia]

Summary

This error was reported:

ArgumentError (wrong number of arguments (given 2, expected 1)):
solidus_subscriptions (5b4c7052ace3) app/models/solidus_subscriptions/promotion/rules/subscription_creation_order.rb:27:in `eligible?'

And it looks like solidus is not using keyword arguments inside #eligible? so we'll stop doing it here as well, probably wasn't a problem until the ruby version was bumped.

Fixed by #283

Also set the default value to nil so no additional hashes are allocated.

Checklist

Check out our PR guidelines for more details.

The following are mandatory for all PRs:

• [ ] I have written a thorough PR description.
• [ ] I have kept my commits small and atomic.
• [ ] I have used clear, explanatory commit messages.

The following are not always needed:

• 📖 I have updated the README to account for my changes.
• 📑 I have documented new code with YARD.
• 🛣️ I have opened a PR to update the guides.
• ✅ I have added automated tests to cover my changes.
• 📸 I have attached screenshots to demo visual changes.

[kennyadsl]

@elia duplicate of #283 ?

[elia]

@kennyadsl yes, rebasing and renaming to just avoid the extra allocation 👍👍👍

[kennyadsl]

@nirebu since this is not covered by specs here, do you have any chance to test if this change will work?

[elia]

Closing, as the impact of this is negligible as the method is generally called forwarding the options arg.