Add missing ${misc:Built-Using} to Built-Using on ai3-tutorial-2-app.

Changes-By: lintian-brush
Fixes: lintian: missing-built-using-field-for-golang-package
See-also: https://lintian.debian.org/tags/missing-built-using-field-for-golang-package.html

debian/control

@@ -8,5 +8,6 @@ Standards-Version: 3.9.6
 Package: ai3-tutorial-2-app
 Architecture: any
 Depends: ${shlibs:Depends}, ${misc:Depends}
+Built-Using: ${misc:Built-Using}
 Description: Test application for ai3/tutorial-2
  Just a simple HTTP server.