We use Travis CI to run the build to verify PRs, but it does not report the result to PR page.
For instance, #232 has a checkmark for each pushed commit, but #236 doesn't have it.
So it is possible that we merge PR which breaks the build without being noticed.

I cannot identify the reason of this problem, so suggest using GitHub Actions as a workaround.
It can integrate the build result to each pushed commit without configuration.