lowered flask version requirement based on testing

Author: dmalan

src/cs50/flask.py

@@ -8,7 +8,7 @@
 
     # Only patch 0.12 (in case logging changes in 0.13)
     version = StrictVersion(get_distribution("flask").version)
-    assert version >= StrictVersion("0.12") and version < StrictVersion("0.13")
+    assert version >= StrictVersion("0.11") and version < StrictVersion("0.13")
 
     # Get default logger
     import flask.logging