gitlab-lint: Drop since available tokens are not enough

After the GitLab "Unauthenticated CI lint API may lead to information
disclosure and SSRF" fix shipped with version 13.8.4 the `ci/lint`
endpoints requires authentication but:

1. `$CI_JOB_TOKEN` is not enough
2. `$TEST_GITLAB_AUTH_TOKEN` is not enough either, some extra
   permissions are required

Given that the YAML will get executed in the same pipeline, let's
just drop the lint CI job rather than granting more permissions
than necessary.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

.gitlab-ci.yml

@@ -65,15 +65,6 @@ stages:
   - docker
   - artifacts
 
-lint-ci:
-  stage: test
-  tags:
-    - lightweight
-  image: python
-  script:
-    - echo "$JOBTEMPLATE" | sed -e "s/@BUILD_ID@/20201225.0000/"  | tee test.yml
-    - ./tests/gitlab-lint --endpoint "${CI_API_V4_URL}/ci/lint" --yaml test.yml
-
 prepare:
   stage: prepare
   tags:

tests/gitlab-lint

-#!/usr/bin/env python3
-import argparse
-import json
-import urllib.request
-
-
-def validate(endpoint, ci):
-    content = open(ci).read()
-    data = json.dumps({"content": content}).encode("utf-8")
-    headers = {"Content-Type": "application/json"}
-    request = urllib.request.Request(
-        endpoint, method="POST", data=data, headers=headers
-    )
-    response = urllib.request.urlopen(request)
-    results = json.load(response)
-    valid = results["status"] == "valid"
-    for e in results["errors"]:
-        print("error:", e)
-    print("✅" if valid else "💔", ci, results["status"])
-    return valid
-
-
-if __name__ == "__main__":
-    parser = argparse.ArgumentParser(description="Validate the GitLab CI/CD YAML")
-    parser.add_argument(
-        "--endpoint",
-        type=str,
-        required=True,
-        help="the API endpoint that does the actual validation",
-    )
-    parser.add_argument(
-        "--yaml", type=str, required=True, help="the YAML to be validated",
-    )
-    args = parser.parse_args()
-    valid = validate(args.endpoint, args.yaml)
-    if not valid:
-        raise SystemExit(1)