bom: Include binder and exclude authz

Binder has had release artifacts since 0d25d8f7.
diff --git a/bom/build.gradle b/bom/build.gradle
index 49fcb3c..be2722d 100644
--- a/bom/build.gradle
+++ b/bom/build.gradle
@@ -14,7 +14,7 @@
         // Generate bom using subprojects
         def internalProjects = [
           project.name,
-          'grpc-binder',
+          'grpc-authz',
           'grpc-compiler',
           'grpc-gae-interop-testing-jdk8',
         ]