chore(deps): update actions/upload-artifact action to v6 (#178)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/draft-paper.yaml

@@ -19,7 +19,7 @@ jobs:
           # This should be the path to the paper within your repo.
           paper-path: joss/paper.md
       - name: Upload
-        uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
         with:
           name: paper
           # This is the output path where Pandoc will write the compiled

.github/workflows/test-coverage.yaml

@@ -44,7 +44,7 @@ jobs:
 
       - name: Upload test results
         if: always()
-        uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
         with:
           name: coverage-test-failures
           path: ${{ runner.temp }}/package