[doc] Issue in "Prerequisites"

[slsnow]

Prerequisites:

https://documentation.suse.com/suse-edge/3.0/html/edge/quickstart-eib.html#id-prerequisites-2

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The docs say the following under requirements:

An x86_64 physical host (or virtual machine) running SLES 15 SP5, openSUSE Leap 15.5, or openSUSE Tumbleweed.

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I think we should consider adding a note here to clarify the point that for production use, and if you want support, you should use SLES 15 SP5. Let me know what you think, thanks.

[ranjinimn]

@slsnow Sure, I can add the following:

SLES 15 SP5 is only supported.

If you are okay with this, then I need to make the changes in a couple of other sections throughout documentation.