Revert strict check in buildhtml

Author: jaladh-singhal

tox.ini

@@ -98,7 +98,7 @@ commands =
 
     # Using srtict so we fail with trackbacks and debug mode to have a richer log
     # For full build we disable parallel runs to easy server load
-    buildhtml: bash -c "jupyter-book build --execute --execute-parallel 1 --html -d"
+    buildhtml: bash -c "jupyter-book build --execute --execute-parallel 1 --html --strict -d"
 
 pip_pre =
     predeps: true