Fix 2.12 release badge

Author: gourlaysama

README.md

@@ -1,4 +1,4 @@
-scala-parser-combinators [<img src="https://img.shields.io/travis/scala/scala-parser-combinators.svg"/>](https://travis-ci.org/scala/scala-parser-combinators) [<img src="https://img.shields.io/maven-central/v/org.scala-lang.modules/scala-parser-combinators_2.11.svg?label=latest%20release%20for%202.11"/>](http://search.maven.org/#search%7Cga%7C1%7Cg%3Aorg.scala-lang.modules%20a%3Ascala-parser-combinators_2.11) [<img src="https://img.shields.io/maven-central/v/org.scala-lang.modules/scala-parser-combinators_2.12*.svg?label=latest%20release%20for%202.12"/>](http://search.maven.org/#search%7Cga%7C1%7Cg%3Aorg.scala-lang.modules%20a%3Ascala-parser-combinators_2.12*) [![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/scala/scala-parser-combinators)
+scala-parser-combinators [<img src="https://img.shields.io/travis/scala/scala-parser-combinators.svg"/>](https://travis-ci.org/scala/scala-parser-combinators) [<img src="https://img.shields.io/maven-central/v/org.scala-lang.modules/scala-parser-combinators_2.11.svg?label=latest%20release%20for%202.11"/>](http://search.maven.org/#search%7Cga%7C1%7Cg%3Aorg.scala-lang.modules%20a%3Ascala-parser-combinators_2.11) [<img src="https://img.shields.io/maven-central/v/org.scala-lang.modules/scala-parser-combinators_2.12.svg?label=latest%20release%20for%202.12"/>](http://search.maven.org/#search%7Cga%7C1%7Cg%3Aorg.scala-lang.modules%20a%3Ascala-parser-combinators_2.12) [![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/scala/scala-parser-combinators)
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 ### Scala Standard Parser Combinator Library