Documentation/releases: Add 4.16 release notes template

Signed-off-by: Jason Glenesk <jason.glenesk@amd.corp-partner.google.com>
Change-Id: I42ce11914d7e7b32017747bbc6d3c7ac77e2868b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58758
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

Documentation/releases/coreboot-4.16-relnotes.md

@@ -0,0 +1,16 @@
+Upcoming release - coreboot 4.16
+================================
+
+The 4.16 release is planned for May 2022.
+
+Update this document with changes that should be in the release notes.
+
+* Please use Markdown.
+* See the past few release notes for the general format.
+* The chip and board additions and removals will be updated right
+  before the release, so those do not need to be added.
+
+Significant changes
+-------------------
+
+### Add significant changes here