.github/workflows/: Upgrade to codecov/codecov-action@v6

Author: MLopez-Ibanez

.github/workflows/R.yml

@@ -181,7 +181,7 @@ jobs:
         working-directory: r
 
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           fail_ci_if_error: true
           files: ./r/cobertura.xml

.github/workflows/python.yml

@@ -184,7 +184,7 @@ jobs:
         working-directory: python
 
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           fail_ci_if_error: true
           verbose: true