Make upgrade script executable (#7111)

## What changed?
<!-- Describe what has changed in this PR -->
change the attributes of upgrade.sh

## Why?
<!-- Tell your future self why have you made these changes -->
Making this script executable allows automation. Most likely this is not
used, but just in case.

## Potential risks
<!-- Assuming the worst case, what can be broken when deploying this
change to production? -->
No as I aware

## Documentation
<!-- Have you made sure this change doesn't falsify anything currently
stated in `docs/`? If significant
new behavior is added, have you described that in `docs/`? -->
N/A

## Is hotfix candidate?
<!-- Is this PR a hotfix candidate or does it require a notification to
be sent to the broader community? (Yes/No) -->
Yes