* Delete rebase.yml

No longer required with new built-in GitHub PR merge master feature
Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update CONTRIBUTING.md
Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update greetings.yml
Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update CONTRIBUTING.md
Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* cleanup
Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>