Added XTL installation to gh-pages.yml

Author: dtriand

.github/workflows/gh-pages.yml

@@ -14,6 +14,9 @@ jobs:
       - name: Install dependencies
         run: |
           pip install sphinx sphinx-book-theme myst_parser
+      - name: Install XTL
+        run: |
+          pip install -e .
       - name: Sphinx build
         run: |
           sphinx-build docs/source docs/build