A minor maintenance release that improves documentation and two new third-party store implementations.

CHANGELOG

• Fix typo in README example (#223) @Coteh
• Add link to implementation for CockroachDB (#219) @stephenafamo
• fix CookieStore creation in doc.go (#206) @collinewait
• Add Redis store implementation (#202) @rbcervilla
• README.md: link Cloud Firestore implementation (#201) @tbpg
• Added _ = to indicate there is a return from Save (#197) @adamjack
• Removed unused global var (#199) @muesli