add sphinx_rtd_theme to sphinx workflow

Author: alperaltuntas

.github/workflows/sphinx.yml

@@ -9,16 +9,10 @@ jobs:
       contents: write
     steps:
     - uses: actions/checkout@v4
-    - name: Set up Conda
-      uses: conda-incubator/setup-miniconda@v2
-      with:
-        auto-activate-base: true
-    - name: Install dependencies
-      run: conda install -y sphinx_rtd_theme
     - name: Build HTML
       uses: ammaraskar/sphinx-action@master
       with:
-        pre-build-command: "conda install -y sphinx_rtd_theme"
+        requirements: pip install sphinx_rtd_theme
     - name: Upload artifacts
       uses: actions/upload-artifact@v4
       with: