[20.10] vendor moby/buildkit v0.8.3-31-gc0149372

no change in vendored code

full diff: moby/buildkit@3a1eeca...c014937

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

vendor.conf

@@ -46,7 +46,7 @@ github.com/Microsoft/go-winio                       5b44b70ab3ab4d291a7c1d28afe7
 github.com/Microsoft/hcsshim                        5bc557dd210ff2caf615e6e22d398123de77fc11 # v0.8.9
 github.com/miekg/pkcs11                             210dc1e16747c5ba98a03bcbcf728c38086ea357 # v1.0.3
 github.com/mitchellh/mapstructure                   d16e9488127408e67948eb43b6d3fbb9f222da10 # v1.3.2
-github.com/moby/buildkit                            3a1eeca59a9263613d996ead67d53a4b7d45723d # v0.8.3-29-g3a1eeca5
+github.com/moby/buildkit                            c014937225cba29cfb1d5161fd134316c0e9bdaa # v0.8.3-31-gc0149372
 github.com/moby/sys                                 1bc8673b57550ddf85262eb0fed0aac651a37dab # symlink/v0.1.0 (latest tag, either mount/vXXX, mountinfo/vXXX or symlink/vXXX)
 github.com/moby/term                                3f7ff695adc6a35abc925370dd0a4dafb48ec64d
 github.com/modern-go/concurrent                     bacd9c7ef1dd9b15be4a9909b8ac7a4e313eec94 # 1.0.3