Re-enable Codecov.

.github/workflows/coverage.yml

@@ -0,0 +1,34 @@
+name: 'CodeCov'
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  coverage:
+
+    runs-on: ubuntu-latest
+    name: Create and upload coverage report
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '21'
+          check-latest: true
+          cache: 'maven'
+      - name: Set up Maven
+        uses: stCarolas/setup-maven@v5
+        with:
+          maven-version: 3.9.9
+      - name: Generate coverage with JaCoCo
+        run: mvn -V --color always -ntp clean verify -Pci
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v4.6.0
+        with:
+          files: 'target/site/jacoco/jacoco.xml'
+          token: ${{secrets.CODECOV_TOKEN}}