Update download URL of uptest

[sergenyalcin]

Description of your changes

Change the download URL of uptest.

I have:

• [x] Read and followed Upbound's contribution process.
• [x] Run make reviewable to ensure this PR is ready for review.
• [ ] Added backport release-x.y labels to auto-backport this PR, as appropriate.

How has this code been tested

Tested locally