Set timeout for cloud build and upgrade goland version

[Jeffwan]

This is to solve the build failure in #69
Kubernetes 1.15 has more staging folder and build is slower than 1.12. We need to set timeout explicitly.

1. gcloud build submit by default has 10m timeout. If dependency is large or overlay is slow, it’s possible build timeout. Create a new argument with default 30m timeout

2. Remove vendor copy since it’s build on top of go modules

3. Upgrade Dockerfile golang version to match version in go.mod

Signed-off-by: Jiaxin Shan seedjeffwan@gmail.com

[kubeflow-bot]

This change is 

[terrytangyuan]

/lgtm
/approve

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This pull-request has been approved by: terrytangyuan

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[terrytangyuan]

Thanks!

[terrytangyuan]

/lgtm

[Jeffwan]

CI commands:

/bin/bash -c /mnt/test-data-volume/kubeflow-xgboost-operator-presubmit-build-70-9aa764f-7905-1ef1/src/kubeflow/xgboost-operator//build_image.sh 
/mnt/test-data-volume/kubeflow-xgboost-operator-presubmit-build-70-9aa764f-7905-1ef1/src/kubeflow/xgboost-operator//Dockerfile 
gcr.io/kubeflow-ci/xgboost-operator v1.0

while build_image.sh uses
https://github.com/kubeflow/xgboost-operator/blob/master/build_image.sh#L10-L12

v1.0 is not consumed and that makes the test failure. I change timeout to default 30m for now.