Gammazero Deque Versions Save

What's Changed

• Fix Clear not zeroing items when buffer full
• Update index-out-of-range panic messages

Full Changelog: https://github.com/gammazero/deque/compare/v0.2.0...v0.2.1

• Use generics to define Deque instance for a type
• Require go1.18

Note, this is a breaking change. Upgrading from v0.1.x to v0.2.x requires code changes.

Add RIndex function. Same as Index but searches in opposite direction.

• Add Index, Insert, Remove for doing operations in the middle of the queue
• A nil Deque behaves like an empty Deque that cannot store values, with Len() and Cap() returning 0