Merge "fully support isolation_level parameter in base dialect" into main

diff --cc lib/sqlalchemy/dialects/oracle/base.py
Simple merge

diff --cc lib/sqlalchemy/dialects/postgresql/base.py
Simple merge

diff --cc lib/sqlalchemy/engine/create.py
Simple merge

diff --cc lib/sqlalchemy/engine/interfaces.py
Simple merge

diff --cc lib/sqlalchemy/testing/requirements.py
Simple merge

diff --cc test/requirements.py
Simple merge