Fix permissions issue in ci.yml

Author: uw-amy-bordenave

.github/workflows/ci.yml

@@ -26,5 +26,5 @@ jobs:
             mkdocs-material-
       - run: pip install mkdocs-material
       - run: pip install mkdocs-material[imaging]
-      - run: apt-get install pngquant
+      - run: sudo apt-get install pngquant
       - run: mkdocs gh-deploy --force