🧪 Fix uploading coverage from GHA to Codecov

The `codecov/codecov-action@v4` release of the official
GitHub Action for uploading coverage data to the
Codecov service turned out to be poorly tested alpha
quality software.
It has numerous bugs preventing it from successfully
sending the code coverage information over. So we
must postpone starting to use it until it's stable.

These patch downgrades it to v3 that remains functional
for the time being.

PR #941

Co-authored-by: Sviatoslav Sydorenko <sviat@redhat.com>

.github/workflows/ci-cd.yml

@@ -367,7 +367,7 @@ jobs:
         coverage xml
       shell: bash
     - name: Send coverage data to Codecov
-      uses: codecov/codecov-action@v4
+      uses: codecov/codecov-action@v3
       with:
         files: coverage.xml
         flags: >-

.github/workflows/reusable-linters.yml

@@ -61,7 +61,7 @@ jobs:
       run: |
         make lint
     - name: Send coverage data to Codecov
-      uses: codecov/codecov-action@v4
+      uses: codecov/codecov-action@v3
       with:
         token: ${{ secrets.codecov-token }}
         files: >-

CHANGES/941.contrib.rst

@@ -0,0 +1,7 @@
+`codecov-action <https://github.com/codecov/codecov-action>`_
+has been temporarily downgraded to ``v3``
+in the GitHub Actions CI/CD workflow definitions
+in order to fix uploading coverage to
+`Codecov <https://app.codecov.io/gh/aio-libs/multidict>`_.
+See `this issue <https://github.com/codecov/codecov-action/issues/1252>`_
+for more details.