pin quantecon-book-theme to 0.1.7 (#136)

Author: mmcky

environment.yml

@@ -8,7 +8,7 @@ dependencies:
   - pip:
     - jupyter-book
     - sphinx-multitoc-numbering
-    - quantecon-book-theme
+    - quantecon-book-theme==0.1.7
     - sphinx-tojupyter
     - sphinxext-rediraffe
     - sphinx-exercise