PostgreSQL 13 ユーザ（ロール）のパスワード変更

psql --user myuser postgres

ALTER ROLE myuser WITH PASSWORD 'new_password';

• https://www.postgresql.jp/document/13/html/sql-alterrole.html
• https://www.postgresql.org/docs/13/sql-alterrole.html
• https://stackoverflow.com/questions/12720967/how-to-change-postgresql-user-password