unify zip folder hierarchy

Author: devsaurus

.github/workflows/regression.yaml

@@ -25,7 +25,7 @@ jobs:
       run: |
         pushd src/gen
         make all
-	popd
+        popd
         zip lc4k_core.zip src/gen/*.vhd src/rtl/*.vhd README.md LICENSE
 
     - uses: YosysHQ/setup-oss-cad-suite@v3