Bump symfony/event-dispatcher from 5.4.9 to 5.4.21 in /build/integration#270

dependabot[bot] wants to merge 1 commit intomasteronehappycat/server:masterfrom

dependabot/composer/build/integration/symfony/event-dispatcher-5.4.21onehappycat/server:dependabot/composer/build/integration/symfony/event-dispatcher-5.4.21Copy head branch name to clipboard