support separation of Numeric/Float

in [1] we are considering separating Numeric and Float.
For Alembic PostgreSQL backend we need this isinstance therefore
to check for both Numeric and Float.
By keeping it to these two types, rather than targeting the
NumericCommon type being added in [1], the patch can work with
SQLAlchemy without the separation change as well.

[1] https://gerrit.sqlalchemy.org/c/sqlalchemy/sqlalchemy/+/3587

Change-Id: I0c956ba8797e38a62ea630ab65cd53779bbf1972

alembic/ddl/postgresql.py

@@ -16,6 +16,7 @@
 from typing import Union
 
 from sqlalchemy import Column
+from sqlalchemy import Float
 from sqlalchemy import literal_column
 from sqlalchemy import Numeric
 from sqlalchemy import text
@@ -132,7 +133,7 @@ def compare_server_default(
         metadata_default = metadata_column.server_default.arg
 
         if isinstance(metadata_default, str):
-            if not isinstance(inspector_column.type, Numeric):
+            if not isinstance(inspector_column.type, (Numeric, Float)):
                 metadata_default = re.sub(r"^'|'$", "", metadata_default)
                 metadata_default = f"'{metadata_default}'"