clean the folder first

Signed-off-by: Jess Frazelle <github@jessfraz.com>

.github/workflows/generate-docs.yml

@@ -38,6 +38,7 @@ jobs:
       - name: Generate the docs
         shell: bash
         run: |
+          rm -rf docs/html
           poetry install
           for f in `poetry run python -m pydoc -k kittycad | awk '{ print $1}'`; do poetry run python -m pydoc -w $f; done
           mkdir -p docs/html