Update requirements.txt

Day41-55/code/oa/requirements.txt

@@ -1,7 +1,7 @@
 asn1crypto==0.24.0
 cffi==1.11.5
 cryptography==2.3
-Django==2.0.7
+Django==2.1
 idna==2.7
 pycparser==2.18
 PyMySQL==0.9.2