fix handling coverage artifacts with latest action

Author: mvantellingen

.github/workflows/python-test.yml

@@ -70,20 +70,26 @@ jobs:
     - name: Prepare artifacts
       run: mkdir .coverage-data && mv .coverage.* .coverage-data/
 
-    - uses: actions/upload-artifact@master
+    - uses: actions/upload-artifact@v4
       with:
-        name: coverage-data
-        path: .coverage-data/
+        name: coverage-data-${{ matrix.platform }}-${{ matrix.python-version }}
+        path: .coverage-data/.coverage.*
 
   coverage:
     runs-on: ubuntu-latest
     needs: [test]
     steps:
     - uses: actions/checkout@v4
 
-    - uses: actions/download-artifact@master
+    - name: Merge Artifacts
+      uses: actions/upload-artifact/merge@v4
       with:
-        name: coverage-data
+        delete-merged: true
+
+    - uses: actions/download-artifact@v4
+      with:
+        pattern: coverage-data-*
+        merge-multiple: coverage-data-*
         path: .
 
     - name: Set up Python 3.12