Update webhook docs

I'm using gitlab-ce version 11.7.0 and some fields in the request body payload are not mentioned in the docs. In the case: project.ci_config_path and push_options[]

Would be nice if this were updated in the docs.

Request body payload example:

{
    "object_kind": "push",
    "before": "95790bf891e76fee5e1747ab589903a6a1f80f22",
    "after": "da1560886d4f094c3e6c9ef40349f7d38b5d27d7",
    "ref": "refs/heads/master",
    "checkout_sha": "da1560886d4f094c3e6c9ef40349f7d38b5d27d7",
    "user_id": 4,
    "user_name": "John Smith",
    "user_username": "jsmith",
    "user_email": "john@example.com",
    "user_avatar": "https://s.gravatar.com/avatar/d4c74594d841139328695756648b6bd6?s=8://s.gravatar.com/avatar/d4c74594d841139328695756648b6bd6?s=80",
    "project_id": 15,
    "project": {
        "id": 15,
        "name": "Diaspora",
        "description": "",
        "web_url": "http://example.com/mike/diaspora",
        "avatar_url": null,
        "git_ssh_url": "git@example.com:mike/diaspora.git",
        "git_http_url": "http://example.com/mike/diaspora.git",
        "namespace": "Mike",
        "visibility_level": 0,
        "path_with_namespace": "mike/diaspora",
        "default_branch": "master",
        "ci_config_path": null,
        "homepage": "http://example.com/mike/diaspora",
        "url": "git@example.com:mike/diaspora.git",
        "ssh_url": "git@example.com:mike/diaspora.git",
        "http_url": "http://example.com/mike/diaspora.git"
    },
    "repository": {
        "name": "Diaspora",
        "url": "git@example.com:mike/diaspora.git",
        "description": "",
        "homepage": "http://example.com/mike/diaspora",
        "git_http_url": "http://example.com/mike/diaspora.git",
        "git_ssh_url": "git@example.com:mike/diaspora.git",
        "visibility_level": 0
    },
    "commits": [
        {
            "id": "b6568db1bc1dcd7f8b4d5a946b0b91f9dacd7327",
            "message": "Update Catalan translation to e38cb41.",
            "timestamp": "2011-12-12T14:27:31+02:00",
            "url": "http://example.com/mike/diaspora/commit/b6568db1bc1dcd7f8b4d5a946b0b91f9dacd7327",
            "author": {
                "name": "Jordi Mallach",
                "email": "jordi@softcatala.org"
            },
            "added": [
                "CHANGELOG"
            ],
            "modified": [
                "app/controller/application.rb"
            ],
            "removed": []
        },
        {
            "id": "da1560886d4f094c3e6c9ef40349f7d38b5d27d7",
            "message": "fixed readme",
            "timestamp": "2012-01-03T23:36:29+02:00",
            "url": "http://example.com/mike/diaspora/commit/da1560886d4f094c3e6c9ef40349f7d38b5d27d7",
            "author": {
                "name": "GitLab dev user",
                "email": "gitlabdev@dv6700.(none)"
            },
            "added": [
                "CHANGELOG"
            ],
            "modified": [
                "app/controller/application.rb"
            ],
            "removed": []
        }
    ],
    "total_commits_count": 4,
    "push_options": []
}