ci: Upload code coverage to coveralls

.github/workflows/build.yml

@@ -156,3 +156,20 @@ jobs:
         run: vendor/bin/phpunit --testsuite unit
         env:
           PACT_DO_NOT_TRACK: true
+
+      - name: Coveralls Parallel
+        uses: coverallsapp/github-action@v2
+        with:
+          flag-name: ${{ matrix.php }}-${{ matrix.dependencies }}
+          parallel: true
+          file: test_results/reports/test_coverage_results.xml
+
+  finish:
+    needs: unit
+    if: ${{ always() }}
+    runs-on: ubuntu-latest
+    steps:
+    - name: Coveralls Finished
+      uses: coverallsapp/github-action@v2
+      with:
+        parallel-finished: true

README.md

@@ -7,6 +7,7 @@
 <!-- Please use absolute URLs for all links as the content of this page is synced to docs.pact.io -->
 
 ![Code Analysis & Test](https://github.com/pact-foundation/pact-php/actions/workflows/build.yml/badge.svg)
+[![Coverage Status](https://coveralls.io/repos/github/pact-foundation/pact-php/badge.svg?branch=HEAD)](https://coveralls.io/github/pact-foundation/pact-php?branch=HEAD)
 ![Compatibility Suite](https://github.com/pact-foundation/pact-php/actions/workflows/compatibility-suite.yml/badge.svg)
 [![Packagist](https://img.shields.io/packagist/v/pact-foundation/pact-php?style=flat-square)](https://packagist.org/packages/pact-foundation/pact-php)