mailmap: update megng's contact info. #3844

Job	Run time
smoke (amaranth-lang/amaranth-stdio)	52s
document	53s
smoke (amaranth-lang/amaranth-soc)	1m 8s
check-links	53s
test (3.11)	2m 30s
test (3.12)	3m 14s
test (3.10)	2m 5s
test (pypy-3.10)	3m 54s
smoke (amaranth-lang/amaranth-boards)	41s
test (3.15-dev)	1m 57s
test (3.14)	2m 33s
test (pypy-3.9)	4m 11s
test (3.13)	2m 32s
test (3.9)	2m 22s
test (pypy-3.11)	3m 47s
publish-docs	9s
publish-docs-dev	0s
required	3s
publish-schemas	7s
publish-package	11s
publish-release	0s
	34m 2s

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