Hello,

While running on Gradle 4.8-rc-2, I noticed the upload uri is being constructed incorrectly:

Could not upload to 'https://api.bintray.com/content/nebula/gradle-plugins/gradle-ospackage-plugin/4.9.0-rc.2/value: com/netflix/nebula/value: gradle-ospackage-plugin/value: 4.9.0-rc.2/value: gradle-ospackage-plugin-value: 4.9.0-rc.2.pom'

I debugged this locally and found that an internal api is being used at BintrayUploadTask.groovy#634. This api used to return the groupId, artifactId, and version attributes as a String, but it is now org.gradle.api.provider.Property<String>.

Fortunately, groupId, artifactId, and version are all available on the public MavenPublication interface as Strings, so this can be fixed in a backwards-compatible way.

See also jfrog/build-info#166.