Docs: add note regarding DOCKER_HOST value for Kubernetes executor
Problem to solve
Our documentation on building Docker images with GitLab CI/CD contains an example .gitlab-ci.yml in the use docker-in-docker executor section that shows DOCKER_HOST: tcp://docker:2375/ being set as a variable.
This is absolutely correct, however, it seems like users that are deploying through Kubernetes using dind may be finding this documentation and assuming they must use tcp://docker:2375/ as the value of their DOCKER_HOST variable as well, which won't work.
Proposal
Something, perhaps a note could be added below the .gitlab-ci.yml example that directs users to this documentation that explains the proper value for that variable that they should be using.
Other links/references
The following two tickets were received by support from users that were likely affected by this.