[CHANGELOG] Forword port changelog after release 1.1.5

[lifubang]

1. This is a forword port of CHANGELOG.md changes from the release PR VERSION: release 1.1.8 (Support RISC-V) #3940 .
2. As we propose to release v1.2.0-rc.0, I think we should add some important announcements in Unreleased changes.

[AkihiroSuda]

# Period before issue/PR references.
! grep -n '[0-[9](https://github.com/opencontainers/runc/actions/runs/5634152621/job/15263793371?pr=3946#step:3:10)a-zA-Z][^.] (#[1-9][0-9, #]*)$' CHANGELOG.md
24: * Enforce absolute paths for mounts (#3020, #3717)
38: * Remove tun/tap from the default device rules (#3468)
39: * specconv: avoid mapping "acl" to MS_POSIXACL (#3739)
make: *** [Makefile:185: verify-changelog] Error 1

https://github.com/opencontainers/runc/actions/runs/5634152621/job/15263793371?pr=3946

[kolyshkin]

LGTM