Renovate bot doesn't create Merge Request

[s8525c]

What Renovate type, platform and version are you using?

Renovate as a CI/CD job on GitLab (13.10.1).

Describe the bug

I have a simple GitLab pipeline in which I am using google/cloud-sdk:333.0.0 docker image. Although a new version is available and the renovate bot detects it, no Merge Request is being created.

• renovate.json

{
  "extends": [
    "config:base"
  ]
}

• .gitlab-ci.yml

stages:
  - test-renovate

.test-renovate:
  image: google/cloud-sdk:333.0.0
  stage: test-renovate
  tags:
    - docker
  script:
    - echo "Test renovate"
  when: always

test-renovate-master-branch:
  extends: .test-renovate
  only:
    - master

Relevant debug logs

Click me to see logs

DEBUG: packageFiles with updates (repository=s8525c/test-repo)
       "config": {
         "gitlabci": [
           {
             "packageFile": ".gitlab-ci.yml",
             "deps": [
               {
                 "depName": "google/cloud-sdk",
                 "currentValue": "333.0.0",
                 "replaceString": "google/cloud-sdk:333.0.0",
                 "autoReplaceStringTemplate": "{{depName}}{{#if newValue}}:{{newValue}}{{/if}}{{#if newDigest}}@{{newDigest}}{{/if}}",
                 "datasource": "docker",
                 "depType": "image",
                 "depIndex": 0,
                 "updates": [
                   {
                     "currentVersion": "333.0.0",
                     "newVersion": "335.0.0",
                     "newValue": "335.0.0",
                     "bucket": "major",
                     "newMajor": 335,
                     "newMinor": 0,
                     "updateType": "major",
                     "isSingleVersion": true,
                     "skippedOverVersions": ["334.0.0"],
                     "branchName": "renovate/docker-google-cloud-sdk-335.x"
                   }
                 ],
                 "warnings": [],
                 "fixedVersion": "333.0.0"
               }
             ]
           }
         ]
       }
DEBUG: processRepo() (repository=s8525c/test-repo)
DEBUG: Processing 0 branches:  (repository=s8525c/test-repo)
DEBUG: Calculating hourly PRs remaining (repository=s8525c/test-repo)
DEBUG: currentHourStart=2021-04-07T14:00:00.000+00:00 (repository=s8525c/test-repo)
DEBUG: PR hourly limit remaining: 2 (repository=s8525c/test-repo)
DEBUG: Calculating prConcurrentLimit (20) (repository=s8525c/test-repo)
DEBUG: 0 PRs are currently open (repository=s8525c/test-repo)
DEBUG: PR concurrent limit remaining: 20 (repository=s8525c/test-repo)
DEBUG: Calculated maximum PRs remaining this run (repository=s8525c/test-repo)
       "prsRemaining": 2
DEBUG: PullRequests limit = 2 (repository=s8525c/test-repo)
DEBUG: Calculating branchConcurrentLimit (20) (repository=s8525c/test-repo)
DEBUG: 0 already existing branches found:  (repository=s8525c/test-repo)
DEBUG: Branch concurrent limit remaining: 20 (repository=s8525c/test-repo)
DEBUG: Calculated maximum branches remaining this run (repository=s8525c/test-repo)
       "branchesRemaining": 20
DEBUG: Branches limit = 20 (repository=s8525c/test-repo)
DEBUG: Removing any stale branches (repository=s8525c/test-repo)
DEBUG: config.repoIsOnboarded=true (repository=s8525c/test-repo)
DEBUG: No renovate branches found (repository=s8525c/test-repo)
DEBUG: ensureIssueClosing() (repository=s8525c/test-repo)
DEBUG: Repository timing splits (milliseconds) (repository=s8525c/test-repo)
       "splits": {"init": 1790, "extract": 772, "lookup": 92, "update": 181},
       "total": 2841
DEBUG: http statistics (repository=s8525c/test-repo)
       "hostStats": ["redacted.example.org, 3 requests, 201ms request average, 0ms queue average"],
       "totalRequests": 3
 INFO: Repository finished (repository=s8525c/test-repo)
       "durationMs": 2841
DEBUG: Renovate exiting

Have you created a minimal reproduction repository?

No, I haven't, but the details provided should be enough to reproduce the issue.

[rarkins]

Docker major updates are disabled by default. Add docker:enabledMajor preset as a quick way to enable them

[s8525c]

Splendid! It works just fine, thank you!