`CI_BUILD_TOKEN` is deprecated and removed in 16.0

Info and replacement: https://mssg.ipta.demokritos.gr/gitlab/help/ci/variables/deprecated_variables.md CI_JOB_TOKEN

It is used here: https://gitlab.com/foxfarmroad/semantic-release-gitlab-docker/-/blob/5dcc1b45dccc232858fbdfacea9b6e36d17e5011/lib/verify.js#L4

Our CI job now fails with:

[8:32:03 AM] [semantic-release] › ✖  Failed step "verifyConditions" of plugin "semantic-release-gitlab-docker"
[8:32:03 AM] [semantic-release] › ✖  An error occurred while running semantic-release: Error: Environment variable CI_BUILD_TOKEN is not set
    at module.exports (/release/node_modules/semantic-release-gitlab-docker/lib/verify.js:6:13)
    at validator (/release/node_modules/semantic-release/lib/plugins/normalize.js:34:30)
    at /release/node_modules/semantic-release/lib/plugins/pipeline.js:37:40
    at next (/release/node_modules/p-reduce/index.js:17:9)
    at processTicksAndRejections (internal/process/task_queues.js:95:5) {
  pluginName: 'semantic-release-gitlab-docker'
}
AggregateError: 
    Error: Environment variable CI_BUILD_TOKEN is not set
        at module.exports (/release/node_modules/semantic-release-gitlab-docker/lib/verify.js:6:13)
        at validator (/release/node_modules/semantic-release/lib/plugins/normalize.js:34:30)
        at /release/node_modules/semantic-release/lib/plugins/pipeline.js:37:40
        at next (/release/node_modules/p-reduce/index.js:17:9)
    at /release/node_modules/semantic-release/lib/plugins/pipeline.js:54:11
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
    at async Object.pluginsConf.<computed> [as verifyConditions] (/release/node_modules/semantic-release/lib/plugins/index.js:80:11)
    at async run (/release/node_modules/semantic-release/index.js:103:3)
    at async module.exports (/release/node_modules/semantic-release/index.js:269:22)
    at async module.exports (/release/node_modules/semantic-release/cli.js:55:5)