Update actions/upload-artifact action to v6

Author: renovate[bot]

.github/workflows/testing.yml

@@ -71,7 +71,7 @@ jobs:
           make test-cover
 
       - name: Upload coverage
-        uses: actions/upload-artifact@5d5d22a31266ced268874388b861e4b58bb5c2f3 # v4.3.1
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
         with:
           name: coverage-${{ runner.os }}-go-${{ matrix.go }}
           path: coverage.*