GOALS: Mention vendor-extensibility in the intro paragraph

LukeShu · LukeShu · commit eb0db71bce7a · 2022-04-27T15:55:38.000-06:00
Signed-off-by: Luke Shumaker &lt;lukeshu@datawire.io&gt;
diff --git a/GOALS.md b/GOALS.md
@@ -2,7 +2,8 @@
 
 The high-level goal of the Envoy Gateway project is to attract more users to Envoy by lowering barriers to adoption 
 through expressive, extensible, role-oriented APIs that support a multitude of ingress and L7/L4 traffic routing
-use cases.
+use cases; and provide a common foundation for vendors to build value-added products without having to re-engineer
+fundamental interactions.
 
 ## Objectives
 
