Fix deprecated GitHub Actions: upgrade upload-artifact and codecov-action to v4

Co-authored-by: larp0 <[email protected]>

Author: Copilot

.github/workflows/cpp_sdk.yml

@@ -127,7 +127,7 @@ jobs:
     
     - name: Upload coverage to Codecov
       if: matrix.build-type == 'Debug' && matrix.os == 'ubuntu-latest'
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v4
       with:
         file: ./cpp_sdk/build/coverage.info
         flags: cpp_sdk
@@ -242,7 +242,7 @@ jobs:
         ninja docs
     
     - name: Upload documentation
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: cpp-sdk-docs
         path: cpp_sdk/build/docs/html/