chore(os): add RHEL9

[MaineK00n]

What did you implement:

support RHEL 9.

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

$ goval-dictionary fetch redhat 9
INFO[05-20|15:17:57] Fetching...                              URL=https://www.redhat.com/security/data/oval/com.redhat.rhsa-RHEL9.xml.bz2
INFO[05-20|15:17:57] Fetched                                  File=com.redhat.rhsa-RHEL9.xml.bz2 Count=11 Timestamp=2022-05-20T00:46:04
INFO[05-20|15:17:57] Refreshing...                            Family=redhat Version=9
INFO[05-20|15:17:57] Inserting new Definitions... 
11 / 11 [---------------------------------------------------------------------------------] 100.00% ? p/s
INFO[05-20|15:17:57] Finish                                   Updated=11

Checklist:

You don't have to satisfy all of the following.

• Write tests
• Write documentation
• Check that there aren't other open pull requests for the same issue/feature
• Format your source code by make fmt
• Pass the test by make test
• Provide verification config / commands
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: YES

Reference