vendor: update buildkit to v0.31.0-rc1

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/moby/buildkit/cmd/buildkitd/config/gcpolicy.go

@@ -78,7 +78,7 @@ func DefaultGCPolicy(cfg GCConfig, dstat disk.DiskStat) []GCPolicy {
 	return []GCPolicy{
 		// if build cache uses more than 512MB delete the most easily reproducible data after it has not been used for 2 days
 		{
-			Filters:      []string{"type==source.local,type==exec.cachemount,type==source.git.checkout"},
+			Filters:      []string{"type==source.local", "type==exec.cachemount", "type==source.git.checkout"},
 			KeepDuration: Duration{Duration: time.Duration(48) * time.Hour}, // 48h
 			MaxUsedSpace: DiskSpace{Bytes: 512 * 1e6},                       // 512MB
 		},

vendor/modules.txt

@@ -643,7 +643,7 @@ github.com/mitchellh/go-wordwrap
 # github.com/mitchellh/hashstructure/v2 v2.0.2
 ## explicit; go 1.14
 github.com/mitchellh/hashstructure/v2
-# github.com/moby/buildkit v0.30.0-rc2.0.20260610142556-f449174742bf
+# github.com/moby/buildkit v0.31.0-rc1
 ## explicit; go 1.25.9
 github.com/moby/buildkit/api/services/control
 github.com/moby/buildkit/api/types