updated readme links

Author: aaronp

README.md

@@ -2,9 +2,9 @@ Args4c
 ====
 
 [![Build Status](https://travis-ci.org/aaronp/args4c.svg?branch=master)](https://travis-ci.org/aaronp/args4c)
-[![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.github.aaronp/args4c_2.12/badge.png)](https://maven-badges.herokuapp.com/maven-central/com.github.aaronp/args4c_2.12)
+[![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.github.aaronp/args4c_2.13/badge.png)](https://maven-badges.herokuapp.com/maven-central/com.github.aaronp/args4c_2.13)
 [![Coverage Status](https://coveralls.io/repos/github/aaronp/args4c/badge.svg?branch=master)](https://coveralls.io/github/aaronp/args4c?branch=master)
-[![Scaladoc](https://javadoc-badge.appspot.com/com.github.aaronp/args4c_2.12.svg?label=scaladoc)](https://javadoc-badge.appspot.com/com.github.aaronp/args4c_2.12)
+[![Scaladoc](https://javadoc-badge.appspot.com/com.github.aaronp/args4c_2.13.svg?label=scaladoc)](https://javadoc-badge.appspot.com/com.github.aaronp/args4c_2.13)
 
 An "arguments for config" zero-dependency* utility to aid in producing a [lightbend (typesafe) config](https://github.com/lightbend/config) from command-line arguments, as well as some convenience methods for working with configurations such as: