CI fix - version pinning sqlalchemy to 1.x (#381)

Author: srprash

tox.ini

@@ -88,10 +88,11 @@ deps =
 
     ext-flask_sqlalchemy: flask >= 0.10
     ext-flask_sqlalchemy: Flask-SQLAlchemy <= 2.5.1
+    ext-flask_sqlalchemy: sqlalchemy >=1.0.0,<2.0.0
 
-    ext-sqlalchemy: sqlalchemy
+    ext-sqlalchemy: sqlalchemy >=1.0.0,<2.0.0
 
-    ext-sqlalchemy_core: sqlalchemy
+    ext-sqlalchemy_core: sqlalchemy >=1.0.0,<2.0.0
     ext-sqlalchemy_core: testing.postgresql
     ext-sqlalchemy_core: psycopg2