Tests not run for some PRs but required to pass

[leokondrashov]

Describe the bug
Github actions block the merge of the PRs with only changed markdown files. We require code quality and unit tests to pass, but we don't run them for PRs based on changed files.

To Reproduce
Make a PR that changes only markdown files.

Expected behavior
Allow the PR to be merged.

Logs
N/A

Notes
N/A

[leokondrashov]

@JooyoungPark73 Please take a look at #983, for example. We require unit tests to pass, but they are excluded from execution.

[JooyoungPark73]

There is a reference doc regarding this issue. I'll take care of this issue, according to the doc.