Fix CI syntax and use upload-artifact@v4

Author: rwb27

.github/workflows/test.yml

@@ -25,7 +25,7 @@ jobs:
           mv coverage.lcov base-coverage.lcov
 
       - name: Upload code coverage for base branch
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: base-coverage.lcov
           path: ./base-coverage.lcov
@@ -57,15 +57,15 @@ jobs:
         run: pytest --cov=src --cov-report=lcov
 
       - name: Upload code coverage
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
-          name: coverage.lcov
+          name: coverage-${{ matrix.python }}
           path: ./coverage.lcov
 
       - name: Analyse with MyPy
         run: mypy src
 
-test-with-unpinned-deps:
+  test-with-unpinned-deps:
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -88,25 +88,26 @@ test-with-unpinned-deps:
       - name: Format with Ruff
         if: success() || failure()
         run: ruff format --check .
+      
+      - name: Analyse with MyPy
+        if: success() || failure()
+        run: mypy src
 
       - name: Test with pytest
         if: success() || failure()
         run: pytest --cov=src --cov-report=lcov
-      
-      - name: Analyse with MyPy
-        run: mypy src
 
   coverage:
     runs-on: ubuntu-latest
     needs: [base_coverage, test]
     steps:
       - name: Download code coverage report
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
-          name: coverage.lcov
+          name: coverage-3.12
 
       - name: Download code coverage report for base branch
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: base-coverage.lcov