Update kpt definition on landing page (#3095)

Author: bgrant0607

site/index.html

@@ -4,7 +4,7 @@
     <meta charset="UTF-8" />
     <title>kpt - Home</title>
     <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
-    <meta name="description" content="A Git-native, schema-aware, extensible client-side tool for packaging, customizing, validating, and applying Kubernetes resources." />
+    <meta name="description" content="A package-centric toolchain that enables a WYSIWYG configuration authoring, automation, and delivery experience and simplifies managing Kubernetes platforms and KRM-driven infrastructure at scale by manipulating declarative Configuration as Data, separated from the code that transforms it." />
     <meta
       name="viewport"
       content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0"