Add PHP 7.4snapshot to the main build
Add PHP 7.4snapshot to the main build

No stable release is available yet. See https://travis-ci.community/t/php-7-4-release/6197
lubosdz/yii2,Alex-Code/yii2,xiaoliwang/yii2,vchenin/yii2,lubosdz/yii2,bizley/yii2,PowerGamer1/yii2,lubosdz/yii2,rob006/yii2,xiaoliwang/yii2,bizley/yii2,Alex-Code/yii2,LAV45/yii2,vchenin/yii2,rhertogh/yii2,rob006/yii2-dev,mikk150/yii2,Alex-Code/yii2,bizley/yii2,xiaoliwang/yii2,arogachev/yii2,brandonkelly/yii2,mikk150/yii2,arogachev/yii2,rhertogh/yii2,mikehaertl/yii2,yiisoft/yii2,LAV45/yii2,bizley/yii2,yiijan/yii2,fetus-hina/yii2,mikk150/yii2,mikk150/yii2,arogachev/yii2,rob006/yii2,mikehaertl/yii2,yiisoft/yii2,lubosdz/yii2,yiijan/yii2,yiijan/yii2,PowerGamer1/yii2,rob006/yii2-dev,mikk150/yii2,vchenin/yii2,PowerGamer1/yii2,LAV45/yii2,rob006/yii2,vchenin/yii2,PowerGamer1/yii2,mikehaertl/yii2,brandonkelly/yii2,fetus-hina/yii2,Alex-Code/yii2,Alex-Code/yii2,LAV45/yii2,fetus-hina/yii2,rob006/yii2,rhertogh/yii2,brandonkelly/yii2,rhertogh/yii2,mikehaertl/yii2,rob006/yii2-dev,rob006/yii2-dev,arogachev/yii2,yiisoft/yii2,yiisoft/yii2,rob006/yii2-dev,fetus-hina/yii2,xiaoliwang/yii2,yiijan/yii2,brandonkelly/yii2,LAV45/yii2,yiijan/yii2