Upgrade golang.org/x/sys so it builds with Go 1.18

[brettbuddin]

I pulled this down to install it on my M1 Mac, and discovered that it fails to build with Go 1.18 due to a common issue with golang.org/x/sys. I've upgraded it here so things build.

Here's the failure this corrects:

# golang.org/x/sys/unix
../../../go/pkg/mod/golang.org/x/[email protected]/unix/syscall_darwin.1_13.go:29:3: //go:linkname must refer to declared function or variable
../../../go/pkg/mod/golang.org/x/[email protected]/unix/zsyscall_darwin_arm64.1_13.go:27:3: //go:linkname must refer to declared function or variable
../../../go/pkg/mod/golang.org/x/[email protected]/unix/zsyscall_darwin_arm64.1_13.go:40:3: //go:linkname must refer to declared function or variable
../../../go/pkg/mod/golang.org/x/[email protected]/unix/zsyscall_darwin_arm64.go:28:3: //go:linkname must refer to declared function or variable
../../../go/pkg/mod/golang.org/x/[email protected]/unix/zsyscall_darwin_arm64.go:43:3: //go:linkname must refer to declared function or variable
../../../go/pkg/mod/golang.org/x/[email protected]/unix/zsyscall_darwin_arm64.go:59:3: //go:linkname must refer to declared function or variable
../../../go/pkg/mod/golang.org/x/[email protected]/unix/zsyscall_darwin_arm64.go:75:3: //go:linkname must refer to declared function or variable
../../../go/pkg/mod/golang.org/x/[email protected]/unix/zsyscall_darwin_arm64.go:90:3: //go:linkname must refer to declared function or variable
../../../go/pkg/mod/golang.org/x/[email protected]/unix/zsyscall_darwin_arm64.go:105:3: //go:linkname must refer to declared function or variable
../../../go/pkg/mod/golang.org/x/[email protected]/unix/zsyscall_darwin_arm64.go:121:3: //go:linkname must refer to declared function or variable
../../../go/pkg/mod/golang.org/x/[email protected]/unix/zsyscall_darwin_arm64.go:121:3: too many errors

📎 golang/go#51091

[jpriebe]

Thanks, Brett!