Release PlacesPlugin 0.6.0

[LukasPaczos]

Changelog

• Problem with option 'country' #554
• Update ProGuard to support built-in shrinker of Gradle Plugin #582
• Fix for disappearing places picker marker #584
• Maps SDK bump to 6.5.0 #634

Release checklist

• Cut the release branch
• Run through testapp/demo app and test all activities
• Update README.md
• Update CHANGELOG.md
• Change version name to 0.6.0 in gradle.properties
• Publish artifact to Maven Central
• Change version name back to 0.7.0-SNAPSHOT
• Merge the release branch back to master
• Tag v0.6.0-places in GitHub

Post-release @langsmith

• Update constants.js file in android-docs repo
• Generate updated javadocs and add to android-docs repo
• Update the version # in the Mapbox demo app
• Update the version # in the Studio Preview app
• Update the version # in voyage

/cc: @mapbox/android

[langsmith]

🏁🍾