Add CHANGELOG.md entry for offsetToZero()
Add CHANGELOG.md entry for offsetToZero()

See https://github.com/grafana/metrictank/pull/1995

I missed the CHANGELOG.md there

Signed-off-by: Oleg Zaytsev <1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e@olegzaytsev.com>

raintank/metrictank,raintank/metrictank,raintank/metrictank,raintank/metrictank