Is your feature request related to a problem? Please describe.
It is not related to a problem. It's a feature request for signing and verifying with Keyless Mode.¹

Describe the solution you'd like

GoReleaser can use the cosign tool as a command in the sigs section. In order to enable Keyless mode in cosign, we need to pass an environment variable called COSIGN_EXPERIMENTAL=1. So, we've opened another issue to enable passing environment variables to the sigs section. Also, recently, the Kyverno project did the same thing. ²

[ ] - #2657 - @Dentrax

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context

cc: @Dentrax @erkanzileli