Fix README markdown lint issues

Author: Prometheus2677

README.md

@@ -146,8 +146,8 @@ Go to [getting started](GETTING_STARTED.md)
 
 ## Tutorials
 
-- [CockroachDB](database/cockroachdb/TUTORIAL.md)
-- [PostgreSQL](database/postgres/TUTORIAL.md)
+* [CockroachDB](database/cockroachdb/TUTORIAL.md)
+* [PostgreSQL](database/postgres/TUTORIAL.md)
 
 (more tutorials to come)