enable sphinx-proof==0.2.0

Author: mmcky

environment.yml

@@ -13,7 +13,7 @@ dependencies:
     - sphinx-tojupyter==0.3.0
     - sphinxext-rediraffe==0.2.7
     - sphinx-exercise==0.4.1
-    - git+https://github.com/executablebooks/sphinx-proof@main
+    - sphinx-proof==0.2.0
     - ghp-import==1.1.0
     - sphinxcontrib-youtube==1.1.0
     - sphinx-togglebutton==0.3.1