Added gatemate vendor and Updated init file #3429

Job	Run time
check-links	44s
smoke (amaranth-lang/amaranth-boards)	42s
document	45s
test (3.8)	2m 16s
smoke (amaranth-lang/amaranth-stdio)	48s
smoke (amaranth-lang/amaranth-soc)	42s
test (3.9)	2m 14s
test (3.10)	2m 8s
test (3.11)	2m 49s
test (3.12)	3m 29s
test (pypy-3.8)	5m 18s
test (pypy-3.9)	4m 38s
test (pypy-3.10)	4m 40s
test (3.13-dev)	3m 9s
publish-docs	7s
publish-docs-dev	0s
required	1s
publish-package	31s
publish-schemas	9s
publish-release	0s
	35m 10s

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