Compatibility with newer golang.org/x/sys/unix

When using this package (as a dependency of getsentry 0.15) with `golang.org/x/sys/unix` a `golangci-lint` returns following error ``` [/go/pkg/mod/github.com/mattn/go-isatty@v0.0.16/isatty_tcgets.go:7:8: could not import golang.org/x/sys/unix (/go/pkg/mod/golang.org/x/sys@v0.0.0-20220928140112-f11e5e49a4ec/unix/syscall.go:83:23: Slice not declared by package unsafe) ``` Go 1.17