Add picosvg to optimization step

This should help remove `fill-rule="evenodd"` from SVGs, improving where
they can be rendered.

.github/workflows/optimize.yml

@@ -9,11 +9,20 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@master
+
       - uses: actions/setup-node@master
         with:
           node-version: '10.x'
       - run: npm install
       - run: npm run svgo
+
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.10' 
+          cache: 'pip'
+      - run: pip install -r .github/python/requirements.txt
+      - run: for icon in icons/*; do picosvg $icon --output_file $icon; done
+
       - uses: EndBug/add-and-commit@v4
         with:
           add: 'icons'