Update Sponsors page with "Digital Impact Alliance" entry

Please add "Digital Impact Alliance" to the sponsors list here ​https://www.torproject.org/about/sponsors/

Logo should come from this page: ​https://digitalimpactalliance.org/ There's a logo on the bottom left of the page.

Link should point to https://digitalimpactalliance.org/

For the description, please use this text: The Digital Impact Alliance (DIAL) advances digital inclusion to achieve the Sustainable Development Goals (SDGs), so that all women, men and children can benefit from life-enhancing, mobile-based digital services. DIAL is supporting a project to complete a successful ESR transition for Tor Browser to we ensure stability, security, and usability of this core privacy technology on both desktop and mobile.