Update project to use Gradle's plugins{} block

Summary:
This project was still using the legacy Gradle's "apply:" syntax
to apply Gradle Plugins. I'm changing it here to use instead the
`plugins{}` block as it make easier to apply other plugins for publishing later.

Reviewed By: mdvacca

Differential Revision: D46330014

fbshipit-source-id: 5483a717a62d5ab76749026c5203dc96a35d73e7

settings.gradle.kts

@@ -5,6 +5,14 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+pluginManagement {
+  repositories {
+    gradlePluginPortal()
+    mavenCentral()
+    google()
+  }
+}
+
 plugins { id("com.gradle.enterprise").version("3.7.1") }
 
 include(":sample", ":yoga", ":yoga-layout")