upgrade quantecon-book-theme (#190)

Author: mmcky

environment.yml

@@ -7,7 +7,7 @@ dependencies:
   - pip
   - pip:
     - jupyter-book==0.11.2
-    - quantecon-book-theme==0.2.3
+    - quantecon-book-theme==0.3.0
     - sphinx-tojupyter==0.1.2
     - sphinxext-rediraffe==0.2.7
     - sphinx-exercise==0.1.1