Add CI_DEPLOY_FREEZE to table of CI variables

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/233639

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/39354

doc/ci/variables/predefined_variables.md

@@ -48,6 +48,7 @@ Kubernetes-specific environment variables are detailed in the
 | `CI_CONFIG_PATH`                              | 9.4    | 0.5    | The path to CI configuration file. Defaults to `.gitlab-ci.yml`                                                                                                                                                                                                                                                                                                   |
 | `CI_DEBUG_TRACE`                              | all    | 1.7    | Whether [debug logging (tracing)](README.md#debug-logging) is enabled                                                                                                                                                                                                                                                                                      |
 | `CI_DEFAULT_BRANCH`                           | 12.4   | all    | The name of the default branch for the project.                                                                                                                                                                                                                                                                                                            |
+| `CI_DEPLOY_FREEZE`                            | 13.2   | all    | Included with the value `true` if the pipeline runs during a [deploy freeze window](../../user/project/releases/index.md#prevent-unintentional-releases-by-setting-a-deploy-freeze).                                                                                                                                                                                                                                    |
 | `CI_DEPLOY_PASSWORD`                          | 10.8   | all    | Authentication password of the [GitLab Deploy Token](../../user/project/deploy_tokens/index.md#gitlab-deploy-token), only present if the Project has one related.                                                                                                                                                                                                                                    |
 | `CI_DEPLOY_USER`                              | 10.8   | all    | Authentication username of the [GitLab Deploy Token](../../user/project/deploy_tokens/index.md#gitlab-deploy-token), only present if the Project has one related.                                                                                                                                                                                                                                    |
 | `CI_DISPOSABLE_ENVIRONMENT`                   | all    | 10.1   | Marks that the job is executed in a disposable environment (something that is created only for this job and disposed of/destroyed after the execution - all executors except `shell` and `ssh`). If the environment is disposable, it is set to true, otherwise it is not defined at all.                                                                  |