Update ci.yml

Author: karenmajewicz

.github/workflows/ci.yml

@@ -19,7 +19,6 @@ jobs:
         with:
           key: ${{ github.ref }}
           path: .cache
-      - run: apt-get install pngquant 
       - run: pip install git+https://${GH_TOKEN}@github.com/squidfunk/mkdocs-material-insiders.git
       - run: mkdocs gh-deploy --force
 env: