bump docker-credential-helpers v0.6.2

full diff: docker/docker-credential-helpers@5241b46...8a9f93a

includes:

- docker/docker-credential-helpers#29 C.free(unsafe.Pointer(err)) -> C.g_error_free(err)
- docker/docker-credential-helpers#124 pass: changed the way for checking if password-store is initalized
  - addresses docker/docker-credential-helpers#133 docker-credential-pass commits about 10 times every time I run a docker command
- docker/docker-credential-helpers#143 Fix docker-credential-osxkeychain list behaviour in case of missing entry in keychain
- docker/docker-credential-helpers#139 make docker-credential-wincred work like docker-credential-osxkeychain

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit f6a4c76)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor.conf

@@ -13,7 +13,7 @@ github.com/davecgh/go-spew                          346938d642f2ec3594ed81d87446
 github.com/dgrijalva/jwt-go                         a2c85815a77d0f951e33ba4db5ae93629a1530af
 github.com/docker/distribution                      83389a148052d74ac602f5f1d62f86ff2f3c4aa5
 github.com/docker/docker                            200b524eff60a9c95a22bc2518042ac2ff617d07 /~https://github.com/docker/engine # 18.09 branch
-github.com/docker/docker-credential-helpers         5241b46610f2491efdf9d1c85f1ddf5b02f6d962
+github.com/docker/docker-credential-helpers         8a9f93a99ff87f416cc79f267c68151af0026f60 # v0.6.2
 github.com/docker/go                                d30aec9fd63c35133f8f79c3412ad91a3b08be06 # Contains a customized version of canonical/json and is used by Notary. The package is periodically rebased on current Go versions.
 github.com/docker/go-connections                    7395e3f8aa162843a74ed6d48e79627d9792ac55 # v0.4.0
 github.com/docker/go-events                         9461782956ad83b30282bf90e31fa6a70c255ba9