Update go.mod and vendor

vendor/github.com/moby/buildkit/util/system/seccomp_linux.go

@@ -1,29 +0,0 @@
-// +build linux,seccomp
-
-package system
-
-import (
-	"sync"
-
-	"golang.org/x/sys/unix"
-)
-
-var seccompSupported bool
-var seccompOnce sync.Once
-
-func SeccompSupported() bool {
-	seccompOnce.Do(func() {
-		seccompSupported = getSeccompSupported()
-	})
-	return seccompSupported
-}
-
-func getSeccompSupported() bool {
-	if err := unix.Prctl(unix.PR_GET_SECCOMP, 0, 0, 0, 0); err != unix.EINVAL {
-		// Make sure the kernel has CONFIG_SECCOMP_FILTER.
-		if err := unix.Prctl(unix.PR_SET_SECCOMP, unix.SECCOMP_MODE_FILTER, 0, 0, 0); err != unix.EINVAL {
-			return true
-		}
-	}
-	return false
-}