chore(deps): bump phpunit/phpunit from 9.6.33 to 12.5.22 in /php/example_code/s3 (#7867)

chore(deps): bump phpunit/phpunit in /php/example_code/s3

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 9.6.33 to 12.5.22.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/12.5.22/ChangeLog-12.5.md)
- [Commits](sebastianbergmann/phpunit@9.6.33...12.5.22)

---
updated-dependencies:
- dependency-name: phpunit/phpunit
  dependency-version: 12.5.22
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

php/example_code/s3/composer.json

@@ -1,7 +1,7 @@
 {
     "require": {
         "aws/aws-sdk-php": "^3.209",
-        "phpunit/phpunit": "^9.5"
+        "phpunit/phpunit": "^12.5"
     },
     "require-dev": {
     },