Fix CI RPM build (switch to Alma Linux 8). Fix #2997

[utoni]

Please sign (check) the below before submitting the Pull Request:

• I have signed the ntop Contributor License Agreement at https://github.com/ntop/legal/blob/main/individual-contributor-licence-agreement.md
• I have read the contributing guidelines at https://github.com/ntop/nDPI/blob/dev/CONTRIBUTING.md
• I have updated the documentation (in doc/) to reflect the changes made (if applicable)

Link to the related issue:

Describe changes:

This fixes the RPM build by using Alma Linux 8 (RHEL8 compatible).
It's possible that the Github Action Workflow needs to get re-enabled, before cron job takes effect.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[IvanNardi]

@utoni, if I got it right, you successfully run "RPM Build" from you fork. Is that correct?

[utoni]

yea, right :D

[IvanNardi]

Thank you