vendor: github.com/containerd/zfs v1.1.0

- update github.com/mistifyio/go-zfs dependency to github.com/mistifyio/go-zfs/v3,
  which contains various bugfixes, and adds go module support (which required a major
  version update): https://github.com/mistifyio/go-zfs/compare/f784269be439...v3.0.1
- remove github.com/pkg/errors dependency
- various minor cleanups/fixes

Full diff: https://github.com/containerd/zfs/compare/v1.0.0...v1.1.0

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor/github.com/mistifyio/go-zfs/v3/error.go

@@ -0,0 +1,18 @@
+package zfs
+
+import (
+	"fmt"
+)
+
+// Error is an error which is returned when the `zfs` or `zpool` shell
+// commands return with a non-zero exit code.
+type Error struct {
+	Err    error
+	Debug  string
+	Stderr string
+}
+
+// Error returns the string representation of an Error.
+func (e Error) Error() string {
+	return fmt.Sprintf("%s: %q => %s", e.Err, e.Debug, e.Stderr)
+}