fix(cmd/gno/clean): allow to run `gno clean -modcache` from anywhere … #6

Job	Run time
setup	7s
Run Main (gnodev) / Go Build / generated	6s
Run Main (gnodev) / Go Test / test	1m 8s
Run Main (gnodev) / Go Linter / lint	54s
Run Main (gnofaucet) / Go Build / generated	5s
Run Main (gnofaucet) / Go Linter / lint	33s
Run Main (gnofaucet) / Go Test / test	35s
Run Main (gnogenesis) / Go Build / generated	8s
Run Main (gnogenesis) / Go Linter / lint	48s
Run Main (gnogenesis) / Go Test / test	40s
Run Main (gnokeykc) / Go Build / generated	5s
Run Main (gnokeykc) / Go Linter / lint	48s
Run Main (gnokeykc) / Go Test / test	39s
Run Main (gnomd) / Go Build / generated	12s
Run Main (gnomd) / Go Linter / lint	38s
Run Main (gnomd) / Go Test / test	33s
Run Main (gnomigrate) / Go Build / generated	8s
Run Main (gnomigrate) / Go Linter / lint	42s
Run Main (gnomigrate) / Go Test / test	38s
	9m 27s

Provide feedback