fixed build path + instructions to build docs

.github/workflows/deploy-docs.yml

@@ -37,4 +37,4 @@ jobs:
       uses: peaceiris/actions-gh-pages@v3
       with:
         github_token: ${{ secrets.GITHUB_TOKEN }}
-        publish_dir: ./_build/html
+        publish_dir: ./docs/_build/html

docs/docs-readme.md

@@ -0,0 +1,9 @@
+To build the docs you will need to install `pandoc` to convert the `readme.md` into `rst` (the format used by `sphinx`, the docs builder). You can see the installation instructions [here](https://pandoc.org/installing.html).
+
+Then you can build the docs with:
+
+```bash
+rm -r docs/_build
+pandoc -s readme.md -o docs/readme.rst
+pipenv run sphinx-build -M html docs/ docs/_build
+```