[Security] Bump symfony/polyfill-php55 from 1.8.0 to 1.12.0
[Security] Bump symfony/polyfill-php55 from 1.8.0 to 1.12.0

Bumps symfony/polyfill-php55 from 1.8.0 to 1.12.0. **This update includes a security fix.**

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
pborreli/composer-service,pborreli/composer-service,pborreli/composer-service,pborreli/composer-service,pborreli/composer-service