Add M to the ecosystem

M, the 1-character Map: non-nodal, non-autothreading .map(*.some-method):
https://github.com/zoffixznet/perl6-M

Author: zoffixznet

META.list

@@ -779,3 +779,4 @@ https://raw.githubusercontent.com/Altai-man/Slang-Kazu/master/META6.json
 https://raw.githubusercontent.com/ufobat/p6-XML-XPath/master/META.info
 https://raw.githubusercontent.com/stmuk/tap-harness6-prove6/master/META.info
 https://raw.githubusercontent.com/bradclawsie/DB-Rscs/master/META6.json
+https://raw.githubusercontent.com/zoffixznet/perl6-M/master/META6.json