Replace Coveralls by Codecov

We found that Coveralls is not able to merge coverage reports from
different job runs. Since supporting PHP8, we have different code
branches in order to support the old and the new PDO interface.

So, it is crucial to merge coverage reports from two job runs, one
for PHP7.4 and another for PHP8.

.github/workflows/tests.yml

@@ -55,14 +55,13 @@ jobs:
       - name: Run tests
         run: composer run test
 
-      # https://github.com/php-coveralls/php-coveralls#github-actions
-      - name: Upload coverage results to Coveralls
+      # https://github.com/codecov/codecov-action
+      - name: Upload coverage results to Codecov
+        uses: codecov/codecov-action@v1
         if: always() && (matrix.php-version == '7.4' || matrix.php-version == '8.0')
-        env:
-          COVERALLS_REPO_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        run: |
-          composer global require php-coveralls/php-coveralls
-          php-coveralls --coverage_clover=build/logs/clover.xml -v
+        with:
+          files: ./build/logs/clover.xml
+          fail_ci_if_error: true
 
       - name: Upload coverage results to Scrutinizer CI
         if: always() && (matrix.php-version == '7.4' || matrix.php-version == '8.0')

README.rst

@@ -10,8 +10,8 @@ CrateDB PDO Adapter
     :target: https://github.com/crate/crate-pdo/actions?workflow=Docs
     :alt: Build status (documentation)
 
-.. image:: https://coveralls.io/repos/github/crate/crate-pdo/badge.svg?branch=main
-    :target: https://coveralls.io/github/crate/crate-pdo
+.. image:: https://codecov.io/gh/crate/crate-pdo/branch/main/graph/badge.svg
+    :target: https://app.codecov.io/gh/crate/crate-pdo
     :alt: Coverage
 
 .. image:: https://scrutinizer-ci.com/g/crate/crate-pdo/badges/quality-score.png?b=main

codecov.yml

@@ -0,0 +1,8 @@
+# https://docs.codecov.io/docs/common-recipe-list
+
+coverage:
+  status:
+    project:
+      default:
+        target: 85%    # the required coverage value
+        threshold: 3%  # the leniency in hitting the target