add rhdh ai team as codeowner of lightspeed defaults

Signed-off-by: Jordan Dubrick <jdubrick@redhat.com>

Author: Jdubrick

.github/CODEOWNERS

@@ -17,3 +17,6 @@
 # Documentation:
 *.md.gotmpl  @redhat-developer/RHDH-content
 /README.md   @redhat-developer/RHDH-content
+
+# Lightspeed:
+/charts/backstage/vendor/backstage/charts/backstage/files/lightspeed/defaults.yaml @redhat-developer/rhdh-ai