[release-branch.go1.11] doc: add Go 1.11 to release history page
Fixes #27357
Change-Id: I048fbd88a08e8b17fcda3872ee4c78935d5075d8
GitHub-Last-Rev:
a0751eca094d68e9bf005abeb6616eb5b0050190
GitHub-Pull-Request: golang/go#27359
Reviewed-on: https://go-review.googlesource.com/132117
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
(cherry picked from commit
d8067d1da60fb890ba656321e1f293bf7b9ee7f7)
Reviewed-on: https://go-review.googlesource.com/132118
Reviewed-by: Andrew Bonventre <andybons@golang.org>