add LittleFS as partition type

Author: Jason2866

builder/main.py

@@ -202,7 +202,7 @@ def _to_unix_slashes(path):
 def fetch_fs_size(env):
     fs = None
     for p in _parse_partitions(env):
-        if p["type"] == "data" and p["subtype"] in ("spiffs", "fat"):
+        if p["type"] == "data" and p["subtype"] in ("spiffs", "fat", "littlefs"):
             fs = p
     if not fs:
         sys.stderr.write(