enable ci to verify go.mod

[Congrool]

What type of PR is this?

/kind enhancement

What this PR does / why we need it:

Currently, we have no way to check if go.mod in a pr has been tidied. We should do that to make sure all pr has run go mod tidy before being merged.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

other Note

[openyurt-bot]

@Congrool: GitHub didn't allow me to assign the following users: your_reviewer.

Note that only openyurtio members, repo collaborators and people who have commented on this issue/PR can be assigned. Additionally, issues/PRs can only have 10 assignees at the same time. For more information please see the contributor guide

In response to [this](https://github.com/openyurtio/yurt-app-manager/pull/94): > > > >#### What type of PR is this? >/kind enhancement > > > > >#### What this PR does / why we need it: >Currently, we have no way to check if `go.mod` in a pr has been tidied. >We should do that to make sure all pr has run `go mod tidy` before being merged. > >#### Which issue(s) this PR fixes: > >Fixes # > >#### Special notes for your reviewer: > > > >#### Does this PR introduce a user-facing change? > >```release-note > >``` > >#### other Note > > Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.

[codecov[bot]]

Codecov Report

Merging #94 (8e8ad2d) into master (23956e8) will not change coverage. The diff coverage is n/a.

@@          Coverage Diff           @@
##           master     #94   +/-   ##
======================================
  Coverage    9.34%   9.34%           
======================================
  Files          18      18           
  Lines        2258    2258           
======================================
  Hits          211     211           
  Misses       2010    2010           
  Partials       37      37           

Flag	Coverage Δ
unittests	9.34% <ø> (ø)

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[rambohe-ch]

@Congrool It's a good idea to check go mod for pull request, maybe we can also add this feature for other repos.

[rambohe-ch]

/lgtm /approve

[openyurt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Congrool, rambohe-ch

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/openyurtio/yurt-app-manager/blob/master/OWNERS)~~ [rambohe-ch] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[openyurt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Congrool, rambohe-ch

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/openyurtio/yurt-app-manager/blob/master/OWNERS)~~ [rambohe-ch] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[Congrool]

@Congrool It's a good idea to check go mod for pull request, maybe we can also add this feature for other repos.

Sure, I'll add it to openyurt repo as well.