Release EPiServer.Marketing.Testing 3.1.0

What's Changed

• Support Net 6 by @Tson-optimizely in #16
• Fix test cannot auto publish the winner if result is significant by @Tson-optimizely in #17
• Fix AB Testing KPI type cannot dnd content by @Tson-optimizely in #18
• Remove highlight when field validate success by @Tson-optimizely in #19

New Contributors

• @Tson-optimizely made their first contribution in #8

Full Changelog: https://github.com/episerver/content-ab-testing/commits/3.1.0