Github has CI built-in, called Github Actions. You simply need to put into place a configuration file inside of a .github/workflows/ directory. That's it. Nothing else. You can then review the CI operations by going to the "Actions" tab at your Github repository. I've been using Github Actions for a few weeks now after I got pissed off at Travis and quit using them.

Here's an example file. Note that I've got test coverage enabled as well, which https://coveralls.io picks up automatically:

spek@scelia ~/repos/dist-mgr $ cat .github/workflows/github_ci_default
+.yml 

name: CI
on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]
  workflow_dispatch:
jobs:
  test:
    runs-on: ${{ matrix.os }}
    strategy:
      fail-fast: false
      matrix:
        os: ['ubuntu-latest', 'macos-latest', 'windows-latest']
        perl: [ '5.32', '5.28', '5.24', '5.18' ]
        include:
          - perl: '5.32'
            os: ubuntu-latest
            coverage: true
    name: Perl ${{ matrix.perl }} on ${{ matrix.os }}
    steps:
      - uses: actions/checkout@v2
      - name: Set up perl
        uses: shogo82148/actions-setup-perl@v1
        with:
          perl-version: ${{ matrix.perl }}
      - run: perl -V
      - run: cpanm ExtUtils::PL2Bat
      - run: cpanm ExtUtils::MakeMaker
      - run: cpanm --installdeps .
      - name: Run tests (no coverage)
        if: ${{ !matrix.coverage }}
        run: prove -lv t
      - name: Run tests (with coverage)
        if: ${{ matrix.coverage }}
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          cpanm -n Devel::Cover::Report::Coveralls
          cover -ignore Git.pm$ -test -report Coveralls
  finish:
    needs: test
    runs-on: ubuntu-latest
    steps:
      - name: Coveralls Finished
        uses: coverallsapp/github-action@master
        with:
          github-token: ${{ secrets.github_token }}
          parallel-finished: true
[download]

Here's what it looks like on Github.