Remove postgres-specific parameteres to create_engine.

The optimization for "executemany" that was needed in older SQLAlchemy
is no longer needed in 2.0 and default options should work now.

migrations/_alembic/env.py

@@ -1,5 +1,5 @@
 from alembic import context
-from sqlalchemy import engine, engine_from_config, pool
+from sqlalchemy import engine_from_config, pool
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.
@@ -50,22 +50,9 @@ def run_migrations_online() -> None:
     and associate a connection with the context.
 
     """
-    # executemany_* arguments are postgres-specific, need to check dialect
-    url_str = config.get_main_option("sqlalchemy.url")
-    assert url_str is not None, "Expect URL connection defined."
-    url = engine.url.make_url(url_str)
-    if url.get_dialect().name == "postgresql":
-        kwargs = dict(
-            executemany_mode="values",
-            executemany_values_page_size=10000,
-            executemany_batch_page_size=500,
-        )
-    else:
-        kwargs = {}
-
     config_dict = config.get_section(config.config_ini_section)
     assert config_dict is not None, "Expect non-empty configuration"
-    connectable = engine_from_config(config_dict, prefix="sqlalchemy.", poolclass=pool.NullPool, **kwargs)
+    connectable = engine_from_config(config_dict, prefix="sqlalchemy.", poolclass=pool.NullPool)
 
     schema = config.get_section_option("daf_butler_migrate", "schema")
     with connectable.connect() as connection: