Merge pull request #3882 from laplaceyang/relicense

RELICENSE: Grant from laplaceyang.

RELICENSE/laplaceyang.md

+# Permission to Relicense under MPLv2 or any other OSI approved license chosen by the current ZeroMQ BDFL
+
+This is a statement by Xujing Yang (laplaceyang)
+that grants permission to relicense his copyrights in the libzmq C++
+library (ZeroMQ) under the Mozilla Public License v2 (MPLv2) or any other
+Open Source Initiative approved license chosen by the current ZeroMQ
+BDFL (Benevolent Dictator for Life).
+
+A portion of the commits made by the Github handle "laplaceyang", with
+commit author "laplaceyang <laplace2013@outlook.com>", are copyright of Xujing Yang.
+This document hereby grants the libzmq project team to relicense libzmq,
+including all past, present and future contributions of the author listed
+above.
+
+Xujing Yang
+2020/04/22