Please update the dictionary for data type mapping.

Environment details

• Programming language: python
• OS: macOS
• Language runtime version: 3.11.5
• Package version:
  • sqlalchemy: 2.0.31
  • sqlalchemy-spanner: 1.7.0

Steps to reproduce

1. Create table which contains FLOAT32 data type
2. Reflect database objects

from sqlalchemy import create_engine, MetaData

engine = create_engine(
    "spanner+spanner:///projects/PROJECT/instances/INSTANCE/databases/DB"
)

metadata = MetaData()
metadata.reflect(engine)  # KeyError: 'FLOAT32'

This update is crucial for maintaining consistency and accuracy across our systems.

Thanks!