bumped to release version 3.5.6

Author: James Boulton

setup.py

@@ -5,7 +5,7 @@
 
 setup(
     name="dashio",
-    version="3.5.5b ",
+    version="3.5.6",
     description="DashIO interface library",
     long_description=long_description,
     long_description_content_type="text/markdown",