San Francisco-based startup Planet Labs, a company that aims to blanket the skies with low-cost satellites, has raised nearly $140 million from investors that include Russian billionaire Yuri Milner and SpaceX backer Draper Fisher Jurvetson. Now, the company has raised an additional $20 million from an unlikely contender: the venture arm of the International Finance Corporation, a multilateral lending organization that’s part of the World Bank.