Bump phpunit/phpunit from 5.5.4 to 5.6.3#23

dependabot[bot] wants to merge 1 commit intomasterappkr/l5code:masterfrom

dependabot/composer/phpunit/phpunit-5.6.3appkr/l5code:dependabot/composer/phpunit/phpunit-5.6.3Copy head branch name to clipboard