Problem: no relicensing grant for my contributions

Solution: add it

RELICENSE/jcourreges.txt

+# Permission to Relicense under MPLv2
+
+This is a statement by Jérémie Courrèges-Anglas
+that grants permission to relicense its copyrights in the libzmq C++
+library (ZeroMQ) under the Mozilla Public License v2 (MPLv2).
+
+A portion of the commits made by the Github handle "jcourreges", with
+commit author "Jérémie Courrèges-Anglas", are copyright of Jérémie Courrèges-Anglas.
+This document hereby grants the libzmq project team to relicense libzmq,
+including all past, present and future contributions of the author listed above.
+
+Jérémie Courrèges-Anglas
+2018/12/07