Merge 6 release notes into RELEASE_NOTES.md

Cherry pick change Ic4cb2b312e725b53ab64047ef3b59e1c87073a20 from branch chrome/m121
to main.

Change-Id: I7c0f5b08b2dd3a877aefd56cc5d553917b84799c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/786358
Reviewed-by: Heather Miller <hcm@google.com>
7 files changed