The php-composer-security-docker is currently failing.
Sample error console output: https://integration.wikimedia.org/ci/blue/organizations/jenkins/php-composer-security-docker/detail/php-composer-security-docker/8692/pipeline
Relevant error message:
+ git fetch --quiet --update-head-ok --depth 2 https://gerrit.wikimedia.org/r/p/mediawiki/vendor +REL1_35:REL1_35 fatal: Couldn't find remote ref REL1_35 Build step 'Execute shell' marked build as failure
Not quite sure what's going on, just after a quick glance at php.yaml.