fix(http): Add Vary header to allow clients to take content negotiati…

…on into account when caching - take language cookie into account.

internal/controller/ogcapi_controller.go

@@ -555,7 +555,7 @@ func (r *OGCAPIReconciler) mutateHeadersMiddleware(obj metav1.Object, middleware
 			// Other headers
 			CustomResponseHeaders: map[string]string{
 				"Cache-Control": "public, max-age=3600, no-transform",
-				"Vary":          "Accept, Accept-Encoding, Accept-Language",
+				"Vary":          "Cookie, Accept, Accept-Encoding, Accept-Language",
 			},
 		},
 	}