Coveralls coverage is zero

[seprokof]

Hello, thanks for creating this template it helps a lot to start plugin development.

In test GitHub job you provide section to evaluate tests coverage and post it to coveralls.io. After building plugin coverage calculated and posted, but coveralls shows it as 0%.

Steps to reproduce:

1. Generate repo from this template
2. Update .github/workflows/test.yml by removing Kong Enterprice versions
3. Create an account on coveralls.io and add your new repo
4. Kick off GitHub test action
5. Observe coverage in your repo on coveralls.io

Expected result:
step (4): Build successfull
step (5): Coverage greater than 0% shown

Actual result:
step (5): Coverage 0% shown

Going through my steps I've created repo https://github.com/seprokof/kong-plugin , added repo to coveralls.io https://coveralls.io/github/seprokof/kong-plugin and build is https://github.com/seprokof/kong-plugin/actions/runs/5438212946 . I've added little bit of debug info but outputting content of coverage files during the build.

I've checked source of pongo.sh from kong-pongo and saw that you just forward --coverage argument to busted and saw your notice that coverage only calculated for unit tests, but based on content of coverage files I expect to see something greater than zero on coveralls.io.

I detected the only suspicious thing - if you enable verbose output of luacov-coveralls by adding -v switch you will see source_files: 0.