Release version 1.2

This is purely a non-functional release that accommodates the Javaslang -> Vavr project rename.

Maven & Gradle configuration need to be updated to point at the new project name:

<dependency>
  <groupId>in.tazj</groupId>
  <artifactId>vavr-matchers</artifactId>
  <version>1.2</version>
  <scope>test</scope>
</dependency>