Bump the dependencies group with 3 updates (acquia#1808)

Bumps the dependencies group with 3 updates: [php-http/cache-plugin](https://github.com/php-http/cache-plugin), [symfony/flex](https://github.com/symfony/flex) and [phpstan/phpstan](https://github.com/phpstan/phpstan).


Updates `php-http/cache-plugin` from 2.0.0 to 2.0.1
- [Release notes](https://github.com/php-http/cache-plugin/releases)
- [Changelog](https://github.com/php-http/cache-plugin/blob/2.x/CHANGELOG.md)
- [Commits](php-http/cache-plugin@2.0.0...2.0.1)

Updates `symfony/flex` from 2.4.6 to 2.4.7
- [Release notes](https://github.com/symfony/flex/releases)
- [Commits](symfony/flex@v2.4.6...v2.4.7)

Updates `phpstan/phpstan` from 1.12.5 to 1.12.6
- [Release notes](https://github.com/phpstan/phpstan/releases)
- [Changelog](https://github.com/phpstan/phpstan/blob/2.0.x/CHANGELOG.md)
- [Commits](phpstan/phpstan@1.12.5...1.12.6)

---
updated-dependencies:
- dependency-name: php-http/cache-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dependencies
- dependency-name: symfony/flex
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dependencies
- dependency-name: phpstan/phpstan
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: dependencies
...

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