MAINTAINERS: remove Gilles Muller

Gilles Muller passed away on November 17, 2021.  We would like
to thank him for his continued support for the development of
Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
diff --git a/MAINTAINERS b/MAINTAINERS
index 360e9aa..8431e54 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4685,7 +4685,6 @@
 
 COCCINELLE/Semantic Patches (SmPL)
 M:	Julia Lawall <Julia.Lawall@inria.fr>
-M:	Gilles Muller <Gilles.Muller@inria.fr>
 M:	Nicolas Palix <nicolas.palix@imag.fr>
 L:	cocci@inria.fr (moderated for non-subscribers)
 S:	Supported