[coreboot-gerrit] Change in coreboot[master]: Documentation: Update index.md and add 4.18 release notes

[Julius Werner (Code Review)]

Attention is currently required from: Felix Singer, Martin L Roth.
Julius Werner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/64843 )

Change subject: Documentation: Update index.md and add 4.18 release notes
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Patch Set 2:

(1 comment)

File Documentation/releases/coreboot-4.18-relnotes.md:

https://review.coreboot.org/c/coreboot/+/64843/comment/8a7c5d48_28ac5ec0 
PS1, Line 17:
> Sure, I can add it.

Well, it was announced in April so let's count from there. I thought our release cadence was 6 months anyway so it would end up being the next version, but I guess it has become faster now?

Anyway, 4.19 is fine too.