Add client credentials flow

examples/client_credentials_flow.py

@@ -0,0 +1,10 @@
+from spotipy.oauth2 import SpotifyClientCredentials
+import spotipy
+import pprint
+
+client_credentials_manager = SpotifyClientCredentials()
+sp = spotipy.Spotify(client_credentials_manager=client_credentials_manager)
+
+search_str = 'Muse'
+result = sp.search(search_str)
+pprint.pprint(result)