GitLab merge requests use the incorrect id to name MR-based branches

[tobybellwood]

Given a numbered GitLab Merge Request (in this case #2), Lagoon selects the incorrect "id" from the payload to name the environment.

In this case, the environment is named pr-144274375 😢

GitLab webhook payload attached for reference:

{
  "data": {
    "webhooktype": "gitlab",
    "event": "merge_request",
    "body": {
      "object_kind": "merge_request",
      "event_type": "merge_request",
      "user": {
        "id": 2217304,
        "name": "Toby Bellwood",
        "username": "tobybellwood",
        "avatar_url": "https://gitlab.com/uploads/-/system/user/avatar/2217304/avatar.png",
        "email": ""
      },
      "project": {
        "id": 34366620,
        "name": "Drupal9 Base",
        "description": "",
        "web_url": "https://gitlab.com/UseLagoon/drupal9-base",
        "avatar_url": null,
        "git_ssh_url": "git@gitlab.com:UseLagoon/drupal9-base.git",
        "git_http_url": "https://gitlab.com/UseLagoon/drupal9-base.git",
        "namespace": "Lagoon",
        "visibility_level": 20,
        "path_with_namespace": "UseLagoon/drupal9-base",
        "default_branch": "main",
        "ci_config_path": "",
        "homepage": "https://gitlab.com/UseLagoon/drupal9-base",
        "url": "git@gitlab.com:UseLagoon/drupal9-base.git",
        "ssh_url": "git@gitlab.com:UseLagoon/drupal9-base.git",
        "http_url": "https://gitlab.com/UseLagoon/drupal9-base.git"
      },
      "object_attributes": {
        "assignee_id": null,
        "author_id": 2217304,
        "created_at": "2022-03-10 06:00:32 UTC",
        "description": "",
        "head_pipeline_id": null,
        "id": 144274375,
        "iid": 2,
        "last_edited_at": null,
        "last_edited_by_id": null,
        "merge_commit_sha": null,
        "merge_error": null,
        "merge_params": {
          "force_remove_source_branch": "1"
        },
        "merge_status": "preparing",
        "merge_user_id": null,
        "merge_when_pipeline_succeeds": false,
        "milestone_id": null,
        "source_branch": "php81-update",
        "source_project_id": 34366620,
        "state_id": 1,
        "target_branch": "php81",
        "target_project_id": 34366620,
        "time_estimate": 0,
        "title": "Update README.md",
        "updated_at": "2022-03-10 06:00:32 UTC",
        "updated_by_id": null,
        "url": "https://gitlab.com/UseLagoon/drupal9-base/-/merge_requests/2",
        "source": {
          "id": 34366620,
          "name": "Drupal9 Base",
          "description": "",
          "web_url": "https://gitlab.com/UseLagoon/drupal9-base",
          "avatar_url": null,
          "git_ssh_url": "git@gitlab.com:UseLagoon/drupal9-base.git",
          "git_http_url": "https://gitlab.com/UseLagoon/drupal9-base.git",
          "namespace": "Lagoon",
          "visibility_level": 20,
          "path_with_namespace": "UseLagoon/drupal9-base",
          "default_branch": "main",
          "ci_config_path": "",
          "homepage": "https://gitlab.com/UseLagoon/drupal9-base",
          "url": "git@gitlab.com:UseLagoon/drupal9-base.git",
          "ssh_url": "git@gitlab.com:UseLagoon/drupal9-base.git",
          "http_url": "https://gitlab.com/UseLagoon/drupal9-base.git"
        },
        "target": {
          "id": 34366620,
          "name": "Drupal9 Base",
          "description": "",
          "web_url": "https://gitlab.com/UseLagoon/drupal9-base",
          "avatar_url": null,
          "git_ssh_url": "git@gitlab.com:UseLagoon/drupal9-base.git",
          "git_http_url": "https://gitlab.com/UseLagoon/drupal9-base.git",
          "namespace": "Lagoon",
          "visibility_level": 20,
          "path_with_namespace": "UseLagoon/drupal9-base",
          "default_branch": "main",
          "ci_config_path": "",
          "homepage": "https://gitlab.com/UseLagoon/drupal9-base",
          "url": "git@gitlab.com:UseLagoon/drupal9-base.git",
          "ssh_url": "git@gitlab.com:UseLagoon/drupal9-base.git",
          "http_url": "https://gitlab.com/UseLagoon/drupal9-base.git"
        },
        "last_commit": {
          "id": "34e80cb3506a97655c39c029b2e60337eac04305",
          "message": "Update README.md",
          "title": "Update README.md",
          "timestamp": "2022-03-10T06:00:24+00:00",
          "url": "https://gitlab.com/UseLagoon/drupal9-base/-/commit/34e80cb3506a97655c39c029b2e60337eac04305",
          "author": {
            "name": "Toby Bellwood",
            "email": ""
          }
        },
        "work_in_progress": false,
        "total_time_spent": 0,
        "time_change": 0,
        "human_total_time_spent": null,
        "human_time_change": null,
        "human_time_estimate": null,
        "assignee_ids": [],
        "state": "opened",
        "blocking_discussions_resolved": true,
        "action": "open"
      },
      "labels": [],
      "changes": {
        "merge_status": {
          "previous": "unchecked",
          "current": "preparing"
        }
      },
      "repository": {
        "name": "Drupal9 Base",
        "url": "git@gitlab.com:UseLagoon/drupal9-base.git",
        "description": "",
        "homepage": "https://gitlab.com/UseLagoon/drupal9-base"
      }
    },
    "giturl": "git@gitlab.com:UseLagoon/drupal9-base.git",
    "uuid": "61aa420d-b021-4616-9d7d-3f5d75ef8f53"
  }
}