Update setup.py -- version bump

Author: lmcinnes

setup.py

@@ -16,7 +16,7 @@ def readme():
 
 configuration = {
     "name": "umap-learn",
-    "version": "0.5.6",
+    "version": "0.5.7",
     "description": "Uniform Manifold Approximation and Projection",
     "long_description": readme(),
     "long_description_content_type": "text/x-rst",