Fix documentation building (#190)

* Update gh_pages.yml

* Update gh_pages.yml

Author: StrikerRUS

.github/workflows/gh_pages.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Install Python
         uses: actions/setup-python@v2
         with:
-          python-version: '3.x'
+          python-version: '3.9'
       - name: Install package
         run: |
           pip install -r requirements_build.txt
@@ -27,7 +27,7 @@ jobs:
           pip install -r requirements.txt
           make html
       - name: Deploy docs
-        uses: JamesIves/[email protected].3
+        uses: JamesIves/[email protected].8
         with:
           branch: gh-pages
           folder: ${{ github.workspace }}/doc/_build/html