Fails inconsistently

This plugin succeeds or fails seemingly at random with very little output to follow up on. Below is common output:

  with:
    github-token: ***
    path-to-lcov: ./coverage/lcov.info
    coveralls-endpoint: https://coveralls.io
Using lcov file: ./coverage/lcov.info
##[error]Bad response: 500 {"message":"Build processing error.","error":true,"url":""}
##[error]Node run failed with exit code 1

The same check ran from TravisCI and had no problem completing. This seems like a back end issue. Can you make this action more resilient and less error-prone or more verbose so you can debug it?

Here's a link to a random failure and here's a PR made at roughly the same time that passed.

Start with the linked failed and passing GitHub Actions runs, then reproduce the workflow using ./coverage/lcov.info and the Coveralls endpoint shown in the report. Inspect how the action handles the reported 500 response and what output it provides. Done means intermittent failures are handled more reliably or produce enough diagnostic information to investigate them.