Merge branch 'patch-3' into 'master'

Fix phpunit command in the docker example.

Closes https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/issues/1478

See merge request !5147

doc/ci/examples/php.md

@@ -49,7 +49,7 @@ apt-get update -yqq
 apt-get install git -yqq
 # Install phpunit, the tool that we will use for testing
-curl -o /usr/local/bin/phpunit https://phar.phpunit.de/phpunit.phar
+curl -Lo /usr/local/bin/phpunit https://phar.phpunit.de/phpunit.phar
 chmod +x /usr/local/bin/phpunit
 # Install mysql driver