chore(deps): bump github.com/moby/buildkit from 0.12.5 to 0.13.0 (#3072)

Bumps [github.com/moby/buildkit](https://github.com/moby/buildkit) from 0.12.5 to 0.13.0.
- [Release notes](https://github.com/moby/buildkit/releases)
- [Commits](https://github.com/moby/buildkit/compare/v0.12.5...v0.13.0)

---
updated-dependencies:
- dependency-name: github.com/moby/buildkit
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

vendor/github.com/vbatts/tar-split/tar/asm/disassemble.go

@@ -135,13 +135,15 @@ func NewInputTarStream(r io.Reader, p storage.Packer, fp storage.FilePutter) (io
 				}
 				isEOF = true
 			}
-			_, err = p.AddEntry(storage.Entry{
-				Type:    storage.SegmentType,
-				Payload: paddingChunk[:n],
-			})
-			if err != nil {
-				pW.CloseWithError(err)
-				return
+			if n != 0 {
+				_, err = p.AddEntry(storage.Entry{
+					Type:    storage.SegmentType,
+					Payload: paddingChunk[:n],
+				})
+				if err != nil {
+					pW.CloseWithError(err)
+					return
+				}
 			}
 			if isEOF {
 				break

vendor/github.com/vbatts/tar-split/tar/storage/packer.go

@@ -24,13 +24,6 @@ type Unpacker interface {
 	Next() (*Entry, error)
 }
 
-/* TODO(vbatts) figure out a good model for this
-type PackUnpacker interface {
-	Packer
-	Unpacker
-}
-*/
-
 type jsonUnpacker struct {
 	seen seenNames
 	dec  *json.Decoder
@@ -115,13 +108,3 @@ func NewJSONPacker(w io.Writer) Packer {
 		seen: seenNames{},
 	}
 }
-
-/*
-TODO(vbatts) perhaps have a more compact packer/unpacker, maybe using msgapck
-(https://github.com/ugorji/go)
-
-
-Even though, since our jsonUnpacker and jsonPacker just take
-io.Reader/io.Writer, then we can get away with passing them a
-gzip.Reader/gzip.Writer
-*/