[RHELC-1622] Require yum on RHEL 8+ based systems

[bocekm]

The package manager on RHEL 8+ is dnf but for a backwards compatibility reason a yum rpm is available to create symlinks pointing to dnf.

If the yum package is missing, convert2rhel fails because it calls yum.

Having yum as a dependency of convert2rhel on RHEL 8+ based systems will ensure that yum will be available (unless someone intentionally removes yum after the convert2rhel installation but then ¯_(ツ)_/¯).

Jira Issues:

• RHELC-1622

Checklist

• [ ] PR has been tested manually in a VM (either author or reviewer)
• [x] Jira issue has been made public if possible
• [x] [RHELC-] or [HMS-] is part of the PR title
• [x] GitHub label has been added to help with Release notes
• [ ] PR title explains the change from the user's point of view
• [x] Code and tests are documented properly
• [x] The commits are squashed to as few commits as possible (without losing data)
• [ ] When merged: Jira issue has been updated to Release Pending if relevant

[has-bot]

/packit test --labels sanity

---

Comment generated by an automation.

Log | Bot Usage

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 95.83%. Comparing base (ab3bbdd) to head (ccbdac7).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1281 +/- ## ======================================= Coverage 95.83% 95.83% ======================================= Files 55 55 Lines 4756 4756 Branches 836 836 ======================================= Hits 4558 4558 Misses 112 112 Partials 86 86 ``` | [Flag](https://app.codecov.io/gh/oamg/convert2rhel/pull/1281/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=oamg) | Coverage Δ | | |---|---|---| | [centos-linux-7](https://app.codecov.io/gh/oamg/convert2rhel/pull/1281/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=oamg) | `91.02% <ø> (ø)` | | | [centos-linux-8](https://app.codecov.io/gh/oamg/convert2rhel/pull/1281/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=oamg) | `91.95% <ø> (ø)` | | | [centos-linux-9](https://app.codecov.io/gh/oamg/convert2rhel/pull/1281/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=oamg) | `92.00% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=oamg#carryforward-flags-in-the-pull-request-comment) to find out more.

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[r0x0d]

Should we add a test case to this to replicate the description of the ticket? It would be a simple test, I believe... @danmyway

[Venefilyn]

Should we add a test case to this to replicate the description of the ticket? It would be a simple test, I believe... @danmyway

@SerCantus WDYT?

[danmyway]

The integration tests task is triaged for this sprint. I don't see an issue of merging this and including the test later in the cycle. Feel free to merge when you feel like (and the sanity suite is passing) @r0x0d @Venefilyn

[Venefilyn]

/packit test --labels sanity

[r0x0d]

/packit test --labels sanity

retrigger in case of infra problems

[Venefilyn]

/packit build

[Venefilyn]

/packit test --labels sanity