Use URL-encoded PIP_FIND_LINKS to support spaces in paths

tools/offline/scripts/use_pip_cache.sh

@@ -7,8 +7,10 @@ then
     exit 1
 fi
 
+URL_ENCODED_PATH="$(python3 -c "import urllib.parse; print(urllib.parse.quote(input()))" <<< "$PIP_CACHE_DIR")"
+
 export PIP_NO_INDEX=1
-export PIP_FIND_LINKS="$PIP_CACHE_DIR"
+export PIP_FIND_LINKS="file://$URL_ENCODED_PATH"
 
 echo "Disabling pip index and use local cache directory..."