Merge branch 'improve-randomness' of framasky/masto-image-bot into master

My bot @gracyimp@botsin.space gave me the same image twice this morning,
within a few seconds, so I asked myself how to improve the randomness.
Indeed, this allowed my bot to publish some images that never were
published!

bot.py

@@ -32,7 +32,8 @@ def post_img_local(mastodon, text, log, config):
 
     continu = True;
     while continu:
-        file = random.choice(os.listdir(img_path+"/"))
+        secure_random = random.SystemRandom()
+        file = secure_random.choice(os.listdir(img_path+"/"))
         if os.path.isdir(img_path+file):
             img_path = img_path+file+"/"
         else:

config.sample.txt

@@ -10,4 +10,4 @@ spoiler_text: some text here
 limit: 2
 limit_hour: 10
 collection_url: https://source.unsplash.com/collection/<collection>/
-unsplash_client_id: "03ad5bfbaa0acd6c96a728d425e533683ec25e5fb7fcf99f6461720b3d0d75a1"
+unsplash_client_id: 03ad5bfbaa0acd6c96a728d425e533683ec25e5fb7fcf99f6461720b3d0d75a1