Use backup namespace for clean job

[smutel]

What this PR does: Change the target namespace for purge medusa tasks

Which issue(s) this PR fixes: Fixes #1299

Checklist

• [ ] Changes manually tested
• [X] Automated Tests added/updated
• [ ] Documentation added/updated
• [X] CHANGELOG.md updated (not required for documentation PRs)
• [X] CLA Signed: DataStax CLA

[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[smutel]

@adejanovski Could you please tell me what do you think about this PR and tell me how to resolve CI issues ?

[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
1.8% Duplication on New Code

See analysis details on SonarCloud

[adejanovski]

Hi @smutel, I merged this change already in another PR yesterday (with some slight adjustments) but I was not feeling good about it because you're PR was pushed a while ago and we didn't take the time to review it. I've merged this PR so you can get credited for the contribution. Thanks!!