adding more dynamic links for downloads with centos-stream-8

[elreydetoda]

Description

Following up on @ramereth, last PR it looks like the Centos Stream team has added a link for centos stream ISO. So, this PR sets the ISO to the latest version of Centos Stream, and also links to the shasum for the ISO as mentioned here ( since the rate of change for the ISO is so frequent ).

Related Issue

#1361

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (non-breaking change that does not add functionality or fix an issue)

Checklist:

• I have read the CONTRIBUTING document.
• I have run the pre-merge tests locally and they pass. ⬅️ - I don't know how to do this ( don't see anything in the main README.md )
• I have updated the documentation accordingly. ⬅️ - don't know if this is necessary, and don't know which docs I should update.
• I have added tests to cover my changes. ⬅️ - don't know of any specific tests I am supposed to add
• All new and existing tests passed. ⬅️ - it looks like it from the results below
• All commits have been signed-off for the Developer Certificate of Origin.

[tas50]

Thanks @elreydetoda

[elreydetoda]

Thanks @elreydetoda

No problem, thanks for an awesome project!

Also, thanks to @ramereth for doing the initial centos-stream commit, updates, and filing the bug with upstream centos team. 🙂 (see more in #1361)