Bisect_ppx web integrations

Bisect_ppx, the OCaml and Reason coverage tool, supports automatic uploading of coverage reports from CI services...

...to coverage services...

This repo tests all six supported combinations:

• Travis to Coveralls    bisect-ppx-report send-to Coveralls
• Travis to Codecov    bisect-ppx-report send-to Codecov
• CircleCI to Coveralls    bisect-ppx-report send-to Coveralls
• CircleCI to Codecov    bisect_ppx-report send-to Codecov
• GitHub Actions to Coveralls    bisect_ppx-report send-to Coveralls
• GitHub Actions to Codecov    bisect_ppx-report send-to Codecov

Note that Bisect_ppx can be manually integrated with virtually any CI and any coverage services using bisect-ppx-report coveralls. This repo only tests the fully automated integrations supported by the bisect-ppx-report send-to command.