While `local` build, kompose was not recognizing `dockerfile` key
Hence it was breaking the build as mentioned in issue #832.
This PR will fix the issue.
Something within golang.org/x/sys messed up and it doesn't help that we
have three different projects using different versions.
This vendor update specifies a golang.org/x/sys as well as fixes the
previous compiling issues with Windows/Linux/macOS builds.
See issue:
```sh
gox -osarch="darwin/amd64 linux/amd64 linux/arm windows/amd64"
-output="bin/kompose-{{.OS}}-{{.Arch}}" -ldflags="-w -X
github.com/kubernetes/kompose/pkg/version.GITCOMMIT=42e7f0e"
Number of parallel builds: 1
--> windows/amd64: github.com/kubernetes/kompose
--> linux/amd64: github.com/kubernetes/kompose
--> darwin/amd64: github.com/kubernetes/kompose
--> linux/arm: github.com/kubernetes/kompose
1 errors occurred:
--> windows/amd64 error: exit status 2
Stderr: #
github.com/kubernetes/kompose/vendor/golang.org/x/crypto/ssh/terminal
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:42: undefined:
windows.ENABLE_ECHO_INPUT
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:42: undefined:
windows.ENABLE_PROCESSED_INPUT
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:42: undefined:
windows.ENABLE_LINE_INPUT
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:42: undefined:
windows.ENABLE_PROCESSED_OUTPUT
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:43: undefined:
windows.SetConsoleMode
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:62: undefined:
windows.SetConsoleMode
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:67: undefined:
windows.ConsoleScreenBufferInfo
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:68: undefined:
windows.GetConsoleScreenBufferInfo
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:91: undefined:
windows.ENABLE_ECHO_INPUT
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:92: undefined:
windows.ENABLE_PROCESSED_INPUT
vendor/golang.org/x/crypto/ssh/terminal/util_windows.go:92: too many
errors
```
