feat: build for armv6

[caarlos0]

closes #115

[ragazenta]

Hi, thanks for adding arm6 release.

But, I just want to add some notes.

• In nfpm archToDebian map , both arm6 and arm7 is armhf, I think this will be a problem, cmiiw. See https://github.com/goreleaser/nfpm/blob/216b17ffff80a5faad835fc53cbe461322d4bf6a/deb/deb.go#L41
• Official Debian armhf use arm7, but Raspberry Pi OS (Raspbian) use arm6. See: https://wiki.debian.org/ArmPorts
• I think you could use different naming for arm6 debian package.

Sorry if I made it too complicated.

[caarlos0]

ah, you're right, thanks for the heads up @ragazenta

will look into it