Update install docs to reflect 18.04 support

Closes #6602.

PiperOrigin-RevId: 220279585
diff --git a/site/docs/install.md b/site/docs/install.md
index 415ea6e..5a68f26 100644
--- a/site/docs/install.md
+++ b/site/docs/install.md
@@ -7,7 +7,7 @@
 
 See the instructions for installing Bazel on:
 
-*   [Ubuntu Linux (16.04 and 14.04)](install-ubuntu.md)
+*   [Ubuntu Linux](install-ubuntu.md)
 *   [Fedora 25, 26, 27, 28, and CentOS 7](install-redhat.md)
 *   [macOS](install-os-x.md)
 *   [Windows](install-windows.md)