SA20: Adjust compatible SQLAlchemy versions: >=1.4,<2.1

The code, now ready for SQLAlchemy 2.x, will not be compatible with
SQLAlchemy 1.3 any longer.

The reason is that `sqlalchemy.orm.declarative_base` did not exist back
then.

.github/workflows/tests.yml

@@ -22,7 +22,7 @@ jobs:
  os: [ubuntu-latest, macos-latest]
  python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
  cratedb-version: ['5.1.2']
- sqla-version: ['1.3.24', '1.4.45', 'next']
+ sqla-version: ['1.4.45', 'next']
  fail-fast: false
  env:
  CRATEDB_VERSION: ${{ matrix.cratedb-version }}

README.rst

@@ -46,7 +46,7 @@ A Python client library for CrateDB_.
 This library:
 
 - Implements the Python `DB API 2.0`_ specification
-- Includes support for SQLAlchemy_ (>= 1.3.0)
+- Includes support for SQLAlchemy_ >= 1.4.
 
 Prerequisites
 =============

setup.py

@@ -60,7 +60,7 @@ def read(path):
  },
  install_requires=['urllib3>=1.9,<2'],
  extras_require=dict(
- sqlalchemy=['sqlalchemy>=1.0,<1.5',
+ sqlalchemy=['sqlalchemy>=1.4,<2.1',
  'geojson>=2.5.0,<3',
  'backports.zoneinfo<1; python_version<"3.9"'],
  test=['tox>=3,<4',