chore(main): release 2.15.2

[release-please[bot]]

:robot: I have created a release beep boop

2.15.2 (2024-01-03)

Bug Fixes

• Disallow vulnerable guzzle versions (#2536) (d1830ed)
• Php 8.3 deprecated get_class method call without argument (#2509) (8c66021)
• Phpseclib security vulnerability (#2524) (73705c2)

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[bshaffer]

We cannot release this until January 2nd (after the holiday freeze)

[release-please[bot]]

:robot: Release is at https://github.com/googleapis/google-api-php-client/releases/tag/v2.15.2 :sunflower: