Remove unnecessary CI tasks

.github/workflows/build.yaml

@@ -27,13 +27,5 @@ jobs:
       - name: Set up cache
         uses: DeterminateSystems/magic-nix-cache-action@main
 
-      - name: Build docs
+      - name: Build game
         run: nix -L build github:${{ github.repository }}/${{ github.sha }} --no-write-lock-file
-
-      - name: Prepare docs for upload
-        run: cp -r --dereference --no-preserve=mode,ownership result/ public/
-
-      - name: Upload artifact
-        uses: actions/upload-pages-artifact@v3
-        with:
-          path: public/