predicted labels should read "Bird" and not "Tree" by default when use_bird_release()

[bw4sz]

I added a test and updated main.use_bird_release() to make sure that the bird label is automatically assigned instead of "Tree" default.

[bw4sz]

@henrykironde I cleaned up the change in the docs. This should be ready to go.

[henrykironde]

Looks good to me, Can you run yapf -i --recursive deepforest/ --style=.style.yapf and commit amend to clean up this code

deepforest/main.py	(reformatted)
117 
         self.config["score_thresh"] = 0.3
 
         # Set label dictionary to Bird
-        self.label_dict = {"Bird":0}
+        self.label_dict = {"Bird": 0}

[bw4sz]

I added another commit since it gets squashed when merged into main.