Spotipy's cache file, containing spotify auth token, is created with overly broad permissions

Summary The CacheHandler class creates a cache file to store the auth token here: https://github.com/spotipy-dev/spotipy/blob/master/spotipy/cachehandler.pyL93-L98 The file created has rw-r--r-- 644 permissions by default, when it could be locked down to rw------- 600 permissions. I think 600 is ...