docs: fixup breakage in release-calendar
Seems the branch was accidentally changed to no longer match the release. Let's fix that.
Fixes: 9ba636cd ("docs: update calendar and link releases notes for 21.3.8")
Seems the branch was accidentally changed to no longer match the release. Let's fix that.
Fixes: 9ba636cd ("docs: update calendar and link releases notes for 21.3.8")