Upgrade to codecov v4 and fix the token (#2421)

Author: Pierre-Sassoulas

.github/workflows/ci.yaml

@@ -256,7 +256,7 @@ jobs:
         run: |
           coverage combine coverage-linux*/.coverage
           coverage xml -o coverage-linux.xml
-      - uses: codecov/codecov-action@v3
+      - uses: codecov/codecov-action@v4
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true
@@ -267,7 +267,7 @@ jobs:
         run: |
           coverage combine coverage-windows*/.coverage
           coverage xml -o coverage-windows.xml
-      - uses: codecov/codecov-action@v3
+      - uses: codecov/codecov-action@v4
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true
@@ -278,7 +278,7 @@ jobs:
         run: |
           coverage combine coverage-pypy*/.coverage
           coverage xml -o coverage-pypy.xml
-      - uses: codecov/codecov-action@v3
+      - uses: codecov/codecov-action@v4
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true