Add golangci-lint for static check.

[zzheng2020]

Close #48

Add golangci-lint for static check.

[slhmy]

Hi! Thanks for contributing with this PR~

I should appologize to you that I didn't describe clear enough on #69.
It will be nice if you can adjust this PR with the following requirements:

1. Remove .golangci.yml (I will be more prefer to have the default settings, since I don't want to have too many customized options). You can give me reasons if you think keeping it will be better.
2. Combine Golangci Lint & Build and Test action together into one job, this should save some resource (or make build will run twice since test and cilint are in different jobs)

[zzheng2020]

Hi, thanks for the review. :)
I have another question. Do you prefer to use golangci-lint to check existing code, or is it only applied to new pull requests?

[slhmy]

Hi, thanks for the review. :) I have another question. Do you prefer to use golangci-lint to check existing code, or is it only applied to new pull requests?

If could, apply it to existing code, but we may push this target gently (or later). I not so sure if current code can totally pass the check.

I also decide to replace go vet to golangcilint in the make check target (we will need to provide a Ubuntu binary install approach first), but it's another task since this PR seems to aims on Github actions (and the toolkit works better than local binaries).

[zzheng2020]

Hi, the current code cannot pass the check.

set skip-pkg-cache and skip-build-cache to true due to these two issues. issue 1, issue 2.

[slhmy]

LGTM, thanks!

[slhmy]

You will receive invitations to join OJ Lab in your email, also there is a QQ group invitation for the one we can find in our directories o.O