Update requirements.txt

update marshmallow 3.14.1 -> 3.18 to support enum

Author: Aaronnz303

requirements.txt

@@ -15,7 +15,7 @@ idna==3.3
 jdcal==1.4.1
 kiwisolver==1.3.2
 markdown==3.3.6
-marshmallow==3.14.1
+marshmallow==3.18
 matplotlib==3.5.1
 natsort==8.0.2
 networkx==2.6.3