ci(tests): Bump codecov to v3, fix node 12 warning

The following actions uses node12 which is deprecated and will be forced to run on node16: codecov/codecov-action@v2. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/

Author: tony

.github/workflows/tests.yml

@@ -76,7 +76,7 @@ jobs:
           COV_CORE_SOURCE: .
           COV_CORE_CONFIG: .coveragerc
           COV_CORE_DATAFILE: .coverage.eager
-      - uses: codecov/codecov-action@v2
+      - uses: codecov/codecov-action@v3
         with:
           token: ${{ secrets.CODECOV_TOKEN }}