Add more context for onos builds

Change-Id: I541d09529471059bab4fad323e16f1505ef57f54
diff --git a/howto/release/components/index.rst b/howto/release/components/index.rst
index 77c45c5..b46cd67 100644
--- a/howto/release/components/index.rst
+++ b/howto/release/components/index.rst
@@ -6,6 +6,7 @@
 
    onos_components
    onos_dependencies
+   maven_plugins
    voltha-protos
 
    voltha-go.rst
@@ -13,3 +14,4 @@
    voltha-onos
    voltha-openolt-adapter
    voltha-openonu-adapter-go
+