mathlib maintainers

Stream: general

[Johan Commelin]

Update from the Mathlib maintainer team: Big thanks to @Gabriel Ebner and @Reid Barton for all the time and energy they put into maintaining Mathlib. Though they've moved on and aren't actively involved these days, their contributions, insights and dedication helped shape Mathlib into what it is today. We're super grateful for everything they've done and wish them all the best in their current and future adventures!