1. Currently, CI will be triggered only when PR. However, some issues/errors, which might be reported by CI, should be resolved before PR.
2. Upgrade the version of actions/setup-go to v4 & actions/checkout to v3.
3. Support Matrix Testing.

I'm willing to do this optimization. The result could be seen in the 'Actions' bar of my reposiroty (tzq0301/graph) like this.