Avoid default dockerhub pull limit by adding docker login step to travis ci pipeline (codeceptjs#2931)

Author: nikocanvacom

.travis.yml

@@ -23,7 +23,7 @@ addons:
 services:
 - docker
 before_install:
-- docker pull selenium/standalone-chrome:3.141.59-oxygen
+- echo "$DOCKER_PASSWORD" | docker login -u "$DOCKER_USERNAME" --password-stdin && docker pull selenium/standalone-chrome:3.141.59-oxygen
 before_script:
 - docker run -d --net=host --shm-size=2g selenium/standalone-chrome:3.141.59-oxygen
 - export DBUS_SESSION_BUS_ADDRESS=/dev/null