chore(main): release 6.9.0

[release-please[bot]]

:robot: I have created a release beep boop

6.9.0 (2023-10-04)

Features

• add payload to jwt exception (#521) (175edf9)

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[release-please[bot]]

:robot: Release is at https://github.com/firebase/php-jwt/releases/tag/v6.9.0 :sunflower: