Remove upgrade from nav heading (#210)

Author: aimurphy

modules/ROOT/nav.adoc

@@ -2,7 +2,7 @@
 * xref:ROOT:index.adoc[]
 * xref:ROOT:faqs.adoc[]
 
-.Install and upgrade
+.Install
 * xref:install-upgrade:quickstart-helm-installs.adoc[]
 * xref:install-upgrade:quickstart-server-installs.adoc[]
 * xref:install-upgrade:supported-versions.adoc[]
@@ -46,4 +46,4 @@
 *** xref:connectors:sources/kafka.adoc[]
 *** xref:connectors:sources/kinesis.adoc[]
 * xref:operations:scale-cluster.adoc[]
-* xref:operations:troubleshooting.adoc[]
+* xref:operations:troubleshooting.adoc[]