Move DSL namespace from supportLibrary to androidx.

Test: ./gradlew createArchive
Change-Id: I07a66c4685daec2b72c83a8fbff9430ec9764a64
diff --git a/paging/runtime/build.gradle b/paging/runtime/build.gradle
index cd9287f..fd3b1a9 100644
--- a/paging/runtime/build.gradle
+++ b/paging/runtime/build.gradle
@@ -47,7 +47,7 @@
     androidTestImplementation(KOTLIN_STDLIB)
 }
 
-supportLibrary {
+androidx {
     name = "Android Paging-Runtime"
     publish = true
     mavenVersion = LibraryVersions.PAGING