Update libgutenberg for SQLAlchemy 2 compatibility

[eshellman]

libgutenberg requires 'sqlalchemy>=1.4.0,<2.00'
I think this is because changes in the ORM in >2.0.0 break things.

dependencies in other software modules, such as Pandas are beginning to complain about sqlalchemy<2.00. It would be timely to update libgutenberg for compatibility with SQLAlchemy 2.

[eshellman]

pandas' complaint:

/public/vhost/g/gutenberg/private/./lib/python/stats/stats_charts.py:79: UserWarning: pandas only supports SQLAlchemy connectable (engine/connection) or database string URI or sqlite3 DBAPI2 connection. Other DBAPI2 objects are not tested. Please consider using SQLAlchemy.
df = read_sql(fields_sql, db.conn, index_col='date')