ci: add go caching #5990

Job	Run time
setup	3s
Run Main (gnodev) / Go Linter / lint	36s
Run Main (gnodev) / Go Build / generated	6s
Run Main (gnodev) / Go Test / test	57s
Run Main (gnofaucet) / Go Linter / lint	25s
Run Main (gnofaucet) / Go Build / generated	7s
Run Main (gnofaucet) / Go Test / test	24s
Run Main (gnogenesis) / Go Build / generated	6s
Run Main (gnogenesis) / Go Test / test	37s
Run Main (gnogenesis) / Go Linter / lint	29s
Run Main (gnokeykc) / Go Linter / lint	28s
Run Main (gnokeykc) / Go Build / generated	12s
Run Main (gnokeykc) / Go Test / test	36s
Run Main (gnomd) / Go Build / generated	6s
Run Main (gnomd) / Go Test / test	22s
Run Main (gnomd) / Go Linter / lint	16s
Run Main (gnomigrate) / Go Build / generated	12s
Run Main (gnomigrate) / Go Test / test	34s
Run Main (gnomigrate) / Go Linter / lint	20s
	6m 56s

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