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

[Martin L Roth (Code Review)]

Attention is currently required from: Martin L Roth, Julius Werner.
Hello build bot (Jenkins),

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/64843

to look at the new patch set (#2).

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

Signed-off-by: Martin Roth 
Change-Id: I52814ebbae804ea0ff24a7cec0618054029b8b47
---
A Documentation/releases/coreboot-4.18-relnotes.md
M Documentation/releases/index.md
2 files changed, 58 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/43/64843/2