GitLab's GitHub integration is vulnerable to SSRF vulnerability

The GitHub service is vulnerable to a SSRF vulnerability. An attacker may be able to leverage this to make arbitrary `POST` requests in a GitLab instance's internal network. It can also be used to connect to cloud provider's instance metadata API, which may result in the ability to execute commands …

# This file is a template, and might need editing before it works on your project.
# see https://docs.gitlab.com/ce/ci/yaml/README.html for all available options

# you can delete this line if you're not using Docker
image: busybox:latest

before_script:
  - echo "Before script section"
  - echo …