chore(deps): update actions/upload-artifact digest to b4b15b8

Author: renovate[bot]

.github/workflows/ci.yml

@@ -75,7 +75,7 @@ jobs:
         uses: taiki-e/install-action@cargo-llvm-cov
       - name: Run tests with coverage
         run: cargo --locked llvm-cov nextest
-      - uses: actions/upload-artifact@84480863f228bb9747b473957fcc9e309aa96097 # v4
+      - uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4
         if: success() || failure()
         with:
           name: junit.xml