Bump SQLAlchemy==1.3.24 to support lnt on Windows (#33)

LNT crashes on windows on startup with following error in SQLAlchemy:

AttributeError: module 'time' has no attribute 'clock'

The `time.clock` function was removed in Python 3.8, causing this error 
in SQLAlchemy code. The issue was fixed by sqlalchemy/sqlalchemy@003333f

This patch upgrades SQLAlchemy to 1.3.24 which resolves above error.
Version 1.3.24 seemed like a reasonable upgrade containing the required 
fix as it does not contain any backward incompatible changes in some of the 
higher version of SQLAlchemy.

Author: omjavaid

setup.py

@@ -121,7 +121,7 @@
         "Flask-RESTful==0.3.4",
         "Jinja2==2.11.3",
         "MarkupSafe==1.1.1",
-        "SQLAlchemy==1.2.19",
+        "SQLAlchemy==1.3.24",
         "Werkzeug==0.15.6",
         "itsdangerous==0.24",
         "python-gnupg==0.3.7",