chore(deps): update actions/upload-artifact action to v7

Author: renovate[bot]

.github/workflows/build.yml

@@ -24,7 +24,7 @@ jobs:
       - name: Build
         run: pnpm build
       - name: Upload CSS
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: "catppuccin-mdbook-css-files"
           path: dist/