1285 adds module list

[wyli]

fixes #1285

Description

• pycharm 2020 works fine with this pattern

if TYPE_CHECKING:
    from ignite.engine import Engine
    from ignite.metrics import Metric
else:
    Engine, _ = optional_import("ignite.engine", "0.4.2", exact_version, "Engine")
    Metric, _ = optional_import("ignite.metrics", "0.4.2", exact_version, "Metric")

• this PR adds the missing top-level module list

Status

Ready

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).

[wyli]

/integration-test