Remove usage of WarPluginConvention
The type will be removed in Gradle 8.0.
https://github.com/OpenLiberty/ci.gradle/blob/a5f46f503aaf60b54bdb5252f440f2bbcf0d0fff/src/main/groovy/io/openliberty/tools/gradle/utils/LooseWarApplication.groovy#L5
@donat Thank you for bringing this to our attention.
When we add support for Gradle 8, we need to consider all the items on the deprecated list that are scheduled for removal in Gradle 8.0.
We recently added support for Gradle 8 (in release 3.6), and the WarPluginConvention class was still available. I just checked the deprecated list and it says this particular class is scheduled for removal in Gradle 9. So this issue should be part of the effort to support Gradle 9 whenever it comes out. There's not even an RC1 for Gradle 9 at this point. So I am going to close this issue.