Fix Sphinx theme installation in workflow

Author: shnmrt

.github/workflows/docs.yml

@@ -26,7 +26,7 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           pip install .
-          pip install sphinx sphinx-rtd-theme
+          pip install sphinx sphinx_rtd_theme
 
       - name: Build Sphinx HTML
         run: |
@@ -38,4 +38,4 @@ jobs:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: docs/build/html
           publish_branch: gh-pages
-          destination_dir: docs
+          destination_dir: docs