Add Sandbox package option to dev script

General MR

Summary

Adds an optional -s flag to the dev/renovate-dev.sh script that changes the package import targets from the current graduated Big Bang packages to the Sandbox packages instead.

This came up while working on implementing the renovate.json config for a new package currently in Sandbox (Mimir) that we wanted to test before it graduates to Big Bang/Universe/Product.

Relevant logs/screenshots

N/A

Linked Issue

big-bang/apps/sandbox/mimir#18

Upgrade Notices

N/A

dev/TESTING_DEVELOPMENT.md

@@ -48,6 +48,13 @@ export KUBECONFIG=~/.kube/$(aws sts get-caller-identity --query "Arn" --output t
 
 13. Do your dev work. Trigger new renovate pipeline runs from the pipeline schedule.
 
+## Importing Sandbox Packages
+If you would like to import/test against [Sandbox packages](https://repo1.dso.mil/big-bang/apps/sandbox) *instead* of fully supported Big Bang packages, run the script in Step #6 with the `-s` flag:
+
+```
+./dev/renovate-dev.sh -s
+```
+
 ## Destroy
 If you need to destroy the Renovate Dev Setup you can use the following:
 ```