1.2.1

This release makes using an Interator for the backing storage much better.

Total issues resolved: 3

• 130: Update phpunit/phpunit requirement from ^9.0 to ^9.5 thanks to @dependabot-preview[bot]
• 131: Update phpspec/prophecy requirement from ^1.10 to ^1.12 thanks to @dependabot-preview[bot]
• 132: Implement iterator support at getLastKeyPair thanks to @cwreden