see if python 3.9 fixes the copybutton

readthedocs.yml

@@ -6,7 +6,7 @@
 version: 2
 
 build:
-  os: ubuntu-20.04
+  os: ubuntu-22.04
   tools:
     python: "3.9"
     nodejs: "16"
@@ -18,7 +18,9 @@ sphinx:
   fail_on_warning: true
 
 # Optionally build your docs in additional formats such as PDF
-formats: all
+formats:
+  - pdf
+  - htmlzip
 
 # Optionally set the version of Python and requirements required to build your docs
 python: