feat: update field constants from labkit-spec v1.0

    # HTTP method (e.g. "GET", "POST").

    HTTP_METHOD = "method"

    # URL of an HTTP request containing only scheme, host, and path (e.g.

    # "https://example.com/foo"). Query strings and fragments must be omitted to

    # avoid logging sensitive information.

    # URL of an HTTP request containing only scheme, host, and path. Query

    # strings and fragments must be omitted to avoid logging sensitive

    # information.

    HTTP_URL = "url"

    # Duration of any operation in seconds. Not limited to HTTP requests; can be