Update setup.py

The last update should be a minor release, not just a bug fix. This is why I changed 1.2.3 to 1.3.1. See the release to 1.2.3 for latest details in the code base.

Author: TimoK93

setup.py

@@ -2,7 +2,7 @@
 
 setup(
     name="py-ctcmetrics",
-    version="1.2.2",
+    version="1.3.1",
     packages=find_packages(),
     install_requires=[
         "numpy",