Fix "column cons.consrc does not exist"

In a fresh install of LNT on Postgres 12 the upgrade scripts fail when trying to access cons.consrc because of:

sqlalchemy/sqlalchemy#4463

Upgrade sqlalchmey to 1.12.x, which is the first release that has the issue fixed.

Author: cmatthew

setup.py

@@ -121,7 +121,7 @@
         "Flask-RESTful==0.3.4",
         "Jinja2==2.7.2",
         "MarkupSafe==0.23",
-        "SQLAlchemy==1.1.11",
+        "SQLAlchemy==1.2.19",
         "Werkzeug==0.12.2",
         "itsdangerous==0.24",
         "python-dateutil==2.6.0",