Among one-off toy projects shared on HN, probably. In the industry, MySQL is still the dominant system in my experience. Just to check though, Statista has it as dominant [1] as well as 2 other sources that appear to be geared towards sales & marketing research [2] [3].
[1] https://www.statista.com/statistics/809750/worldwide-popular...
[2] https://6sense.com/tech/relational-databases/mysql-market-sh...
[3] https://www.datanyze.com/market-share/databases--272